• new GaN fet

    From John Larkin@21:1/5 to All on Wed Mar 2 13:47:42 2022
    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?

    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Phil Hobbs on Wed Mar 2 18:41:23 2022
    Phil Hobbs wrote:
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?


    It does specify the threshold as -1.5 to -3.5V, but doesn't give the corresponding I_D.

    Nice package--wonder if it comes in DIP? ;)

    (Almost certainly way too rich for my blood, if it's intended for cell
    tower use, but an interesting part, for sure.)

    BTW: they're specifying the output power at *3 dB compression*. Who
    ever heard of that?

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to John Larkin on Wed Mar 2 18:37:23 2022
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?


    It does specify the threshold as -1.5 to -3.5V, but doesn't give the corresponding I_D.

    Nice package--wonder if it comes in DIP? ;)

    (Almost certainly way too rich for my blood, if it's intended for cell
    tower use, but an interesting part, for sure.)

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Wed Mar 2 16:12:58 2022
    On Wed, 2 Mar 2022 18:51:58 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?


    BTW EPC has a very interesting report on reliability vs. gate drive for
    their GaN FET parts. You really really don't want to exceed 8V.

    <https://epc-co.com/epc/DesignSupport/eGaNFETReliability/ReliabilityReportPhase14.aspx>

    Cheers

    Phil Hobbs

    I took some data on EPC gate degradation vs time, when biased above +5
    volts. In my tests, high gate voltage caused increased gate leakage
    over hours or days, but the parts still worked.

    High drain voltages have a soft leakage that's not destructive if the
    current is limited.

    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Wed Mar 2 16:15:04 2022
    On Wed, 2 Mar 2022 18:37:23 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?


    It does specify the threshold as -1.5 to -3.5V, but doesn't give the >corresponding I_D.

    Nice package--wonder if it comes in DIP? ;)

    (Almost certainly way too rich for my blood, if it's intended for cell
    tower use, but an interesting part, for sure.)

    Cheers

    Phil Hobbs

    I like that package. The EPC BGAs are a pain and can't get heat out.

    I'll try to get pricing and samples.

    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to John Larkin on Wed Mar 2 18:51:58 2022
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?


    BTW EPC has a very interesting report on reliability vs. gate drive for
    their GaN FET parts. You really really don't want to exceed 8V.

    <https://epc-co.com/epc/DesignSupport/eGaNFETReliability/ReliabilityReportPhase14.aspx>

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Wed Mar 2 19:15:00 2022
    On Wed, 2 Mar 2022 18:41:23 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Hobbs wrote:
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?


    It does specify the threshold as -1.5 to -3.5V, but doesn't give the
    corresponding I_D.

    Nice package--wonder if it comes in DIP? ;)

    (Almost certainly way too rich for my blood, if it's intended for cell
    tower use, but an interesting part, for sure.)

    BTW: they're specifying the output power at *3 dB compression*. Who
    ever heard of that?

    It's very common in RF power amplifiers, often the final amplifier in
    a radio transmitter, striking a balance between linearity and output
    power capability. One also sees 1 dB compression.

    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Joe Gwinn on Wed Mar 2 19:35:10 2022
    Joe Gwinn wrote:
    On Wed, 2 Mar 2022 18:41:23 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Hobbs wrote:
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?


    It does specify the threshold as -1.5 to -3.5V, but doesn't give the
    corresponding I_D.

    Nice package--wonder if it comes in DIP? ;)

    (Almost certainly way too rich for my blood, if it's intended for cell
    tower use, but an interesting part, for sure.)

    BTW: they're specifying the output power at *3 dB compression*. Who
    ever heard of that?

    It's very common in RF power amplifiers, often the final amplifier in
    a radio transmitter, striking a balance between linearity and output
    power capability. One also sees 1 dB compression.

    Joe Gwinn

    1 dB I know about. But 3 dB, really?

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Clifford Heath@21:1/5 to Joe Gwinn on Thu Mar 3 11:48:51 2022
    On 3/3/22 11:15 am, Joe Gwinn wrote:
    On Wed, 2 Mar 2022 18:41:23 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Hobbs wrote:
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?


    It does specify the threshold as -1.5 to -3.5V, but doesn't give the
    corresponding I_D.

    Nice package--wonder if it comes in DIP? ;)

    (Almost certainly way too rich for my blood, if it's intended for cell
    tower use, but an interesting part, for sure.)

    BTW: they're specifying the output power at *3 dB compression*. Who
    ever heard of that?

    It's very common in RF power amplifiers, often the final amplifier in
    a radio transmitter, striking a balance between linearity and output
    power capability. One also sees 1 dB compression.

    P1db is more common, but less relevant in a pulse application.
    The data sheet introduction does say they can sustain linear operation,
    but these devices seem to be specified mainly for pulse applications
    like radar, c.f. the quiescent drain current of 15mA. No way you're
    gonna build a linear amp with such a low drain current.

    CH

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Rich S@21:1/5 to Clifford Heath on Wed Mar 2 20:27:20 2022
    On Thursday, March 3, 2022 at 12:49:03 AM UTC, Clifford Heath wrote:
    On 3/3/22 11:15 am, Joe Gwinn wrote:
    On Wed, 2 Mar 2022 18:41:23 -0500, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:

    Phil Hobbs wrote:
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to richsulinengineer@gmail.com on Wed Mar 2 20:54:28 2022
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    On Thursday, March 3, 2022 at 12:49:03 AM UTC, Clifford Heath wrote:
    On 3/3/22 11:15 am, Joe Gwinn wrote:
    On Wed, 2 Mar 2022 18:41:23 -0500, Phil Hobbs
    <pcdhSpamM...@electrooptical.net> wrote:

    Phil Hobbs wrote:
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.



    --

    I yam what I yam - Popeye

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Gerhard Hoffmann@21:1/5 to All on Thu Mar 3 06:32:58 2022
    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to jlarkin@highlandsniptechnology.com on Thu Mar 3 08:51:12 2022
    On a sunny day (Wed, 02 Mar 2022 20:54:28 -0800) it happened jlarkin@highlandsniptechnology.com wrote in <0fi02hpt58odbjru88is7fpa4amta15lml@4ax.com>:

    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    On Thursday, March 3, 2022 at 12:49:03 AM UTC, Clifford Heath wrote:
    On 3/3/22 11:15 am, Joe Gwinn wrote:
    On Wed, 2 Mar 2022 18:41:23 -0500, Phil Hobbs
    <pcdhSpamM...@electrooptical.net> wrote:

    Phil Hobbs wrote:
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Those are just illusions, BUILD the circuit and test!

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to jlarkin@highland_atwork_technology. on Thu Mar 3 08:47:56 2022
    On a sunny day (Wed, 02 Mar 2022 13:47:42 -0800) it happened John Larkin <jlarkin@highland_atwork_technology.com> wrote in <m9pv1h14dnn607t97es8530mg8mo787ijt@4ax.com>:

    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?

    Yes
    I sort of like the datasheet
    Notation like 2.2-j2.3 shows capacitance effect etc.
    ?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Gerhard Hoffmann on Thu Mar 3 08:39:10 2022
    Gerhard Hoffmann wrote:
    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    "Stop, you're both right." ;)

    Cheers

    Phil Hobbs

    (former RF guy)

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pNaonStpealmtje@yahoo.com on Thu Mar 3 07:22:49 2022
    On Thu, 03 Mar 2022 08:51:12 GMT, Jan Panteltje
    <pNaonStpealmtje@yahoo.com> wrote:

    On a sunny day (Wed, 02 Mar 2022 20:54:28 -0800) it happened >jlarkin@highlandsniptechnology.com wrote in ><0fi02hpt58odbjru88is7fpa4amta15lml@4ax.com>:

    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S >><richsulinengineer@gmail.com> wrote:

    On Thursday, March 3, 2022 at 12:49:03 AM UTC, Clifford Heath wrote:
    On 3/3/22 11:15 am, Joe Gwinn wrote:
    On Wed, 2 Mar 2022 18:41:23 -0500, Phil Hobbs
    <pcdhSpamM...@electrooptical.net> wrote:

    Phil Hobbs wrote:
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Those are just illusions, BUILD the circuit and test!

    I like to Spice things to prepare my instincts, and get close to a
    working circuit. Less soldering. That blows up fewer expensive parts
    too.



    --

    I yam what I yam - Popeye

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to All on Thu Mar 3 07:21:06 2022
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    And what's wrong with knowing drain current as a function of gate
    voltage? RF data sheets usually say "turn the trimpot until the RF
    comes out."

    I wonder how people generate those "design kits" if they don't know
    the basic electrical properties of the part. Maybe it's like "load
    pull" engineering.







    --

    I yam what I yam - Popeye

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pNaonStpealmtje@yahoo.com on Thu Mar 3 07:32:04 2022
    On Thu, 03 Mar 2022 08:47:56 GMT, Jan Panteltje
    <pNaonStpealmtje@yahoo.com> wrote:

    On a sunny day (Wed, 02 Mar 2022 13:47:42 -0800) it happened John Larkin ><jlarkin@highland_atwork_technology.com> wrote in ><m9pv1h14dnn607t97es8530mg8mo787ijt@4ax.com>:

    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?

    Yes
    I sort of like the datasheet

    I don't! The part is supposedly untuned, but the few impedances are
    specified from 3400 to 3800 MHz. Strange.

    Notation like 2.2-j2.3 shows capacitance effect etc.
    ?

    At a single frequency and bias condition, in a power amp. A Spice
    model would include the nonlinear capacitances and the inductances,
    which might matter for RF. They sure matter in wideband time domain.

    They might sell more parts if they considered a wider range of use
    than a power amp over one small band.



    --

    I yam what I yam - Popeye

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to jlarkin@highlandsniptechnology.com on Thu Mar 3 11:12:30 2022
    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    And what's wrong with knowing drain current as a function of gate
    voltage? RF data sheets usually say "turn the trimpot until the RF
    comes out."

    I wonder how people generate those "design kits" if they don't know
    the basic electrical properties of the part. Maybe it's like "load
    pull" engineering.


    They probably make about eight of them over the lifetime of the part, so statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Thu Mar 3 08:25:27 2022
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    And what's wrong with knowing drain current as a function of gate
    voltage? RF data sheets usually say "turn the trimpot until the RF
    comes out."

    I wonder how people generate those "design kits" if they don't know
    the basic electrical properties of the part. Maybe it's like "load
    pull" engineering.


    They probably make about eight of them over the lifetime of the part, so >statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so
    they emphasize analytical, necessarily linear, ideas like s-params and
    Smith charts. Things that could be sort-of handled with pencils and
    slide rules.

    The nonlinear stuff became load-pull, basically documenting a few
    bench tests.

    The EPC GaN fets have Spice models and LT Spice examples, probably
    because the intended market is switching power supplies.

    The Cree SiC fets have Spice models, for the same reason.



    --

    I yam what I yam - Popeye

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to All on Thu Mar 3 08:46:44 2022
    On Thu, 03 Mar 2022 08:25:27 -0800, jlarkin@highlandsniptechnology.com
    wrote:

    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs ><pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    And what's wrong with knowing drain current as a function of gate
    voltage? RF data sheets usually say "turn the trimpot until the RF
    comes out."

    I wonder how people generate those "design kits" if they don't know
    the basic electrical properties of the part. Maybe it's like "load
    pull" engineering.


    They probably make about eight of them over the lifetime of the part, so >>statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so
    they emphasize analytical, necessarily linear, ideas like s-params and
    Smith charts. Things that could be sort-of handled with pencils and
    slide rules.

    The nonlinear stuff became load-pull, basically documenting a few
    bench tests.

    The EPC GaN fets have Spice models and LT Spice examples, probably
    because the intended market is switching power supplies.

    The Cree SiC fets have Spice models, for the same reason.


    So different semiconductor companies have different cultures, and
    declare their parts to be time domain (switching) parts or frequency
    domain (RF) parts, and cut their market roughly in half.

    If they spec a part for narrowband RF, they want even fewer customers.

    We're trying to use a Hittite RF switch to route time-domain signals,
    arbitrary waveforms and pulses in a laser modulator. The data sheet is terrible. I'm waiting to see if their support people really understand
    the part. Like, what's the capacitance of the switch control pin? Why
    is the low frequency limit 100 MHz?

    There might be uses for RF switches in electro-optical gadgets. We're
    measuring stuff.

    We discovered that, for the switch under consideration, "reflective
    switch" means that it shorts the deselected input port! I suppose
    that's technically correct. Some "reflective" switches open the
    unselected port. In the RF world, I guess it's all the same.







    --

    I yam what I yam - Popeye

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to jlarkin@highlandsniptechnology.com on Thu Mar 3 12:00:59 2022
    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 03 Mar 2022 08:25:27 -0800, jlarkin@highlandsniptechnology.com
    wrote:

    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    And what's wrong with knowing drain current as a function of gate
    voltage? RF data sheets usually say "turn the trimpot until the RF
    comes out."

    I wonder how people generate those "design kits" if they don't know
    the basic electrical properties of the part. Maybe it's like "load
    pull" engineering.


    They probably make about eight of them over the lifetime of the part, so >>> statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so
    they emphasize analytical, necessarily linear, ideas like s-params and
    Smith charts. Things that could be sort-of handled with pencils and
    slide rules.

    The nonlinear stuff became load-pull, basically documenting a few
    bench tests.

    The EPC GaN fets have Spice models and LT Spice examples, probably
    because the intended market is switching power supplies.

    The Cree SiC fets have Spice models, for the same reason.


    So different semiconductor companies have different cultures, and
    declare their parts to be time domain (switching) parts or frequency
    domain (RF) parts, and cut their market roughly in half.

    If they spec a part for narrowband RF, they want even fewer customers.

    We're trying to use a Hittite RF switch to route time-domain signals, arbitrary waveforms and pulses in a laser modulator. The data sheet is terrible. I'm waiting to see if their support people really understand
    the part. Like, what's the capacitance of the switch control pin? Why
    is the low frequency limit 100 MHz?

    There might be uses for RF switches in electro-optical gadgets. We're measuring stuff.

    We discovered that, for the switch under consideration, "reflective
    switch" means that it shorts the deselected input port! I suppose
    that's technically correct. Some "reflective" switches open the
    unselected port. In the RF world, I guess it's all the same.

    At 4 GHz, a short becomes an open if you hang a two-inch cable on it.
    RF folks are very fond of that sort of pure frequency domain trick.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tom Gardner@21:1/5 to jlarkin@highlandsniptechnology.com on Thu Mar 3 17:10:41 2022
    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    And what's wrong with knowing drain current as a function of gate
    voltage? RF data sheets usually say "turn the trimpot until the RF
    comes out."

    I wonder how people generate those "design kits" if they don't know
    the basic electrical properties of the part. Maybe it's like "load
    pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so
    they emphasize analytical, necessarily linear, ideas like s-params and
    Smith charts. Things that could be sort-of handled with pencils and
    slide rules.

    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.
    There are lots of /enforceable/ regulations to prevent that,
    with an associated squad of men in black suits.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to spamjunk@blueyonder.co.uk on Thu Mar 3 09:14:28 2022
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    And what's wrong with knowing drain current as a function of gate
    voltage? RF data sheets usually say "turn the trimpot until the RF
    comes out."

    I wonder how people generate those "design kits" if they don't know
    the basic electrical properties of the part. Maybe it's like "load
    pull" engineering.


    They probably make about eight of them over the lifetime of the part, so >>> statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so
    they emphasize analytical, necessarily linear, ideas like s-params and
    Smith charts. Things that could be sort-of handled with pencils and
    slide rules.

    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are
    used small-signal.

    There are lots of /enforceable/ regulations to prevent that,
    with an associated squad of men in black suits.


    --

    I yam what I yam - Popeye

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Thu Mar 3 09:39:10 2022
    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de> >>>>>> wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function >>>>>> of time?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    And what's wrong with knowing drain current as a function of gate
    voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >>>>>> the basic electrical properties of the part. Maybe it's like "load >>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so >>>>> statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so
    they emphasize analytical, necessarily linear, ideas like s-params and >>>> Smith charts. Things that could be sort-of handled with pencils and
    slide rules.

    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are
    used small-signal.

    There are lots of /enforceable/ regulations to prevent that,
    with an associated squad of men in black suits.

    The part is specified at its *3 dB* compression point. Pretty hard to
    avoid lotsa distortion there!

    Cheers

    Phil Hobbs

    It must be hard to simulate frequency-hopping complex-constellation multiple-antenna RF systems. That's probably the big use for
    million-dollar oscilloscopes.

    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to jlarkin@highlandsniptechnology.com on Thu Mar 3 12:20:12 2022
    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de> >>>>> wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function >>>>> of time?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    And what's wrong with knowing drain current as a function of gate
    voltage? RF data sheets usually say "turn the trimpot until the RF
    comes out."

    I wonder how people generate those "design kits" if they don't know
    the basic electrical properties of the part. Maybe it's like "load
    pull" engineering.


    They probably make about eight of them over the lifetime of the part, so >>>> statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so
    they emphasize analytical, necessarily linear, ideas like s-params and
    Smith charts. Things that could be sort-of handled with pencils and
    slide rules.

    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are
    used small-signal.

    There are lots of /enforceable/ regulations to prevent that,
    with an associated squad of men in black suits.

    The part is specified at its *3 dB* compression point. Pretty hard to
    avoid lotsa distortion there!

    Cheers

    Phil Hobbs


    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Thu Mar 3 15:52:13 2022
    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de> >>>>>> wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function >>>>>> of time?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    And what's wrong with knowing drain current as a function of gate
    voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >>>>>> the basic electrical properties of the part. Maybe it's like "load >>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so >>>>> statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so
    they emphasize analytical, necessarily linear, ideas like s-params and >>>> Smith charts. Things that could be sort-of handled with pencils and
    slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically
    tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are
    used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    There are lots of /enforceable/ regulations to prevent that,
    with an associated squad of men in black suits.

    Yes. NTIA.


    The part is specified at its *3 dB* compression point. Pretty hard to
    avoid lotsa distortion there!

    Yeah, but DC to RF efficiency is higher, which is OK is one can afford
    a bigger output filtering system.

    Often, intermediate driver amps (which drive the final amp) are 3db,
    but the final amps (which drives the antenna) are 1 dB.


    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to All on Thu Mar 3 13:13:01 2022
    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs ><pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de> >>>>>>> wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function >>>>>>> of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >>>>>>> the basic electrical properties of the part. Maybe it's like "load >>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so >>>>>> statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >>>>> they emphasize analytical, necessarily linear, ideas like s-params and >>>>> Smith charts. Things that could be sort-of handled with pencils and
    slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically
    tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are
    used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    A few competitors will spend big bucks to measure the enemies parts,
    and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs
    until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Their data sheets should have a giant header that shouts

    FOR RF USE ONLY



    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to jlarkin@highland_atwork_technology. on Thu Mar 3 17:08:32 2022
    On Thu, 03 Mar 2022 13:13:01 -0800, John Larkin <jlarkin@highland_atwork_technology.com> wrote:

    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs >><pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de> >>>>>>>> wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function >>>>>>>> of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >>>>>>>> the basic electrical properties of the part. Maybe it's like "load >>>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >>>>>> they emphasize analytical, necessarily linear, ideas like s-params and >>>>>> Smith charts. Things that could be sort-of handled with pencils and >>>>>> slide rules.

    Yes. Well before computers. And the key was finding the right >>mathematical and physical approximations, yielding an analytically >>tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are >>>> used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    A few competitors will spend big bucks to measure the enemies parts,
    and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs
    until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Yes, but they *do* have them.

    Actually, much of what they make is better simulated using a full EM
    field solver, which spice cannot touch.

    My guess is that if they published simplified spice models, they would
    get endless questions about this or that inaccuracy, so they avoid the
    expense by not issuing such models.


    Their data sheets should have a giant header that shouts

    FOR RF USE ONLY

    They do, "MiniCircuts", right at the top of every page.

    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Lasse Langwadt Christensen@21:1/5 to All on Thu Mar 3 14:12:20 2022
    torsdag den 3. marts 2022 kl. 22.13.17 UTC+1 skrev John Larkin:
    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joeg...@comcast.net>
    wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs ><pcdhSpamM...@electrooptical.net> wrote:

    jla...@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spam...@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jla...@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamM...@electrooptical.net> wrote:

    jla...@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk...@arcor.de> >>>>>>> wrote:

    Am 03.03.22 um 05:54 schrieb jla...@highlandsniptechnology.com: >>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsuli...@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function >>>>>>> of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >>>>>>> the basic electrical properties of the part. Maybe it's like "load >>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >>>>> they emphasize analytical, necessarily linear, ideas like s-params and >>>>> Smith charts. Things that could be sort-of handled with pencils and >>>>> slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically >tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are >>> used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.
    A few competitors will spend big bucks to measure the enemies parts,
    and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs
    until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Their data sheets should have a giant header that shouts

    FOR RF USE ONLY

    would that stop you?

    and isn't the RF use only implied with specs only covering RF?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Joe Gwinn on Thu Mar 3 17:21:34 2022
    Joe Gwinn wrote:
    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de> >>>>>>> wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function >>>>>>> of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >>>>>>> the basic electrical properties of the part. Maybe it's like "load >>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so >>>>>> statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >>>>> they emphasize analytical, necessarily linear, ideas like s-params and >>>>> Smith charts. Things that could be sort-of handled with pencils and
    slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically
    tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are
    used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    There are lots of /enforceable/ regulations to prevent that,
    with an associated squad of men in black suits.

    Yes. NTIA.


    The part is specified at its *3 dB* compression point. Pretty hard to
    avoid lotsa distortion there!

    Yeah, but DC to RF efficiency is higher, which is OK is one can afford
    a bigger output filtering system.

    Often, intermediate driver amps (which drive the final amp) are 3db,
    but the final amps (which drives the antenna) are 1 dB.

    The point being that TG was talking out of his, um, lower back.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Joe Gwinn on Thu Mar 3 17:43:15 2022
    Joe Gwinn wrote:
    On Thu, 03 Mar 2022 13:13:01 -0800, John Larkin <jlarkin@highland_atwork_technology.com> wrote:

    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de> >>>>>>>>> wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function >>>>>>>>> of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >>>>>>>>> the basic electrical properties of the part. Maybe it's like "load >>>>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >>>>>>> they emphasize analytical, necessarily linear, ideas like s-params and >>>>>>> Smith charts. Things that could be sort-of handled with pencils and >>>>>>> slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically
    tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are >>>>> used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    A few competitors will spend big bucks to measure the enemies parts,
    and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs
    until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Yes, but they *do* have them.

    You know this how, exactly?

    Actually, much of what they make is better simulated using a full EM
    field solver, which spice cannot touch.

    SPICE is a pretty capable package for solving sparse systems of
    nonlinear ODEs, with a few features bolted on for other things such as transmission lines. (A transmission line has invisible internal state,
    and so can't be simulated by ODEs.)

    It doesn't model carrier diffusion, which is probably its worst
    deficiency in high speed circuitry. Second worst is that its noise
    simulation capability is very limited--it's just a linearized propagation-of-errors calculation based on a single operating point. In reality, many noise sources don't behave that way--for instance, shot
    noise depends on the instantaneous current, so noise correlations with
    signal can be far from negligible in real life.

    But most of those things aren't done any better by your average
    full-wave EM code, which has zero information about the circuit
    properties and probably couldn't do carrier dynamics to save its virtual
    life, even if you gave it a physical description of the circuit with the required spatial resolution everywhere. (This would not be your elegant lightweight input file, you understand.)

    I wrote a clusterized optimizing FDTD code for my antenna-coupled MIM
    tunnel junction work about 15 years ago, so I have relevant experience.

    My guess is that if they published simplified spice models, they would
    get endless questions about this or that inaccuracy, so they avoid the expense by not issuing such models.

    Op amp makers have the inaccuracy problem in spades, which they handle
    by lying through their teeth AFAICT--they say that better models would
    reveal too much about their designs, or run too slowly, or put warts on everybody's nose, or something.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to langwadt@fonz.dk on Thu Mar 3 16:02:11 2022
    On Thu, 3 Mar 2022 14:12:20 -0800 (PST), Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:

    torsdag den 3. marts 2022 kl. 22.13.17 UTC+1 skrev John Larkin:
    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joeg...@comcast.net>
    wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs
    <pcdhSpamM...@electrooptical.net> wrote:

    jla...@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spam...@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jla...@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamM...@electrooptical.net> wrote:

    jla...@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk...@arcor.de> >> >>>>>>> wrote:

    Am 03.03.22 um 05:54 schrieb jla...@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsuli...@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    And what's wrong with knowing drain current as a function of gate
    voltage? RF data sheets usually say "turn the trimpot until the RF >> >>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >> >>>>>>> the basic electrical properties of the part. Maybe it's like "load >> >>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >> >>>>> they emphasize analytical, necessarily linear, ideas like s-params and >> >>>>> Smith charts. Things that could be sort-of handled with pencils and
    slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically
    tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are >> >>> used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.
    A few competitors will spend big bucks to measure the enemies parts,
    and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs
    until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Their data sheets should have a giant header that shouts

    FOR RF USE ONLY

    would that stop you?


    Of course not. We use RF parts in pulse applications all the time.

    and isn't the RF use only implied with specs only covering RF?

    Yes. They can afford to blow off us time-domain buyers.

    Actually, the SAV-5xx data sheets have DC drain curves! That's way
    more than most RF parts reveal.

    We measured a lot more.

    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to All on Thu Mar 3 15:56:44 2022
    On Thu, 03 Mar 2022 17:08:32 -0500, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Thu, 03 Mar 2022 13:13:01 -0800, John Larkin ><jlarkin@highland_atwork_technology.com> wrote:

    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs >>><pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de> >>>>>>>>> wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function >>>>>>>>> of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >>>>>>>>> the basic electrical properties of the part. Maybe it's like "load >>>>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >>>>>>> they emphasize analytical, necessarily linear, ideas like s-params and >>>>>>> Smith charts. Things that could be sort-of handled with pencils and >>>>>>> slide rules.

    Yes. Well before computers. And the key was finding the right >>>mathematical and physical approximations, yielding an analytically >>>tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are >>>>> used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    A few competitors will spend big bucks to measure the enemies parts,
    and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs >>until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Yes, but they *do* have them.

    Then they lied to me more than once.


    Actually, much of what they make is better simulated using a full EM
    field solver, which spice cannot touch.


    Field solver for a phemt?


    My guess is that if they published simplified spice models, they would
    get endless questions about this or that inaccuracy, so they avoid the >expense by not issuing such models.

    Best avoid s-params too.



    Their data sheets should have a giant header that shouts

    FOR RF USE ONLY

    They do, "MiniCircuts", right at the top of every page.

    Joe Gwinn

    Is that what "minicircuits" means? RF only?

    I made a nice wideband step attenuator with a SAV-541. It's not
    obvious from the data sheet that this would work. I started with
    Phil's spice model for the SAV-551.

    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Gerhard Hoffmann@21:1/5 to All on Fri Mar 4 05:10:09 2022
    Am 03.03.22 um 16:21 schrieb jlarkin@highlandsniptechnology.com:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    We talked about pin diode switches last week. Do you know
    the carrier lifetime of the diodes? Does Spice have any
    idea what that might be? And this is THE parameter that
    makes PIN diodes happen.

    And the voltage exactly when/where on a polysilicon gate.
    End, feed point, somewhere in between?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    What with noise calculations in a nonlinear environment?
    Try that with Spice in a chopper amplifier.

    Which operating point would you choose in the chopper
    amplifier? Switch at A or B? You must make up your mind;
    noise analysis has not the concept of time.

    It takes harmonic balance methods to do it.

    Spice is NOT a large-signal simulator. What you get is
    small signal behavior around approximated operating points
    that shift around as crazy as a function of time.

    Transient analysis is wrapped around the small signal linear
    analysis as just another layer.


    And what's wrong with knowing drain current as a function of gate
    voltage? RF data sheets usually say "turn the trimpot until the RF
    comes out."

    I wonder how people generate those "design kits" if they don't know
    the basic electrical properties of the part. Maybe it's like "load
    pull" engineering.

    Ask THEM for example:
    < https://www.minicircuits.com/applications/Modelithics.html >

    X-parameters are like s-parameters, only large signal.

    < https://www.modelithics.com/FreeDownloads/Brochures/Modelithics_GaN_Modeling_1705.pdf
    >

    You also get ADS design kits fom NXP, or Infineon etc.
    < https://www.nxp.com/products/radio-frequency/rf-high-power-models/models-for-ads-keysight-advanced-design-system:RF_HIGH_POWER_MODELS_KEYSIGHT
    >

    cheers, Gerhard










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  • From Jan Panteltje@21:1/5 to jlarkin@highland_atwork_technology. on Fri Mar 4 08:41:25 2022
    On a sunny day (Thu, 03 Mar 2022 13:13:01 -0800) it happened John Larkin <jlarkin@highland_atwork_technology.com> wrote in <sgb22hp17vp6tad22b0e900asqnpjikmqt@4ax.com>:

    Their data sheets should have a giant header that shouts

    FOR RF USE ONLY

    John, that is their market.
    If you want to use your bike for mountain climbing you cannot demand all bike manufacturers to give specs for that.
    It is NOT that hard to make a test circuit and measure things, I do that with most new to me devices
    including Minicircuits (you actually gave me the idea to try some of their stuff (mixers)..)
    If it works it works, I have done spice simulation that told me things did not work that I used for many years
    without problems...
    Spice may be nice for complex filters etc, but there are better programs for that
    the rest really needs just hands on experience and UNDERSTANDING about how them electrons like to move.
    And the time factor, test maybe be an afternoon and even bending a PCB trace makes lot of difference,
    spice you can do for weeks, have then nothing you can be sure about that works :-)
    Imagine WW3 and you only have a hand full of BC547 or something that survived the EMP and now you need to build that radio
    No spice bummer...
    No problem for me.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pNaonStpealmtje@yahoo.com on Fri Mar 4 06:36:25 2022
    On Fri, 04 Mar 2022 08:41:25 GMT, Jan Panteltje
    <pNaonStpealmtje@yahoo.com> wrote:

    On a sunny day (Thu, 03 Mar 2022 13:13:01 -0800) it happened John Larkin ><jlarkin@highland_atwork_technology.com> wrote in ><sgb22hp17vp6tad22b0e900asqnpjikmqt@4ax.com>:

    Their data sheets should have a giant header that shouts

    FOR RF USE ONLY

    John, that is their market.

    They have defined it as such, so deliberately discouraged a large
    class of potential customers. That's weird.


    If you want to use your bike for mountain climbing you cannot demand all bike manufacturers to give specs for that.
    It is NOT that hard to make a test circuit and measure things, I do that with most new to me devices
    including Minicircuits (you actually gave me the idea to try some of their stuff (mixers)..)

    We do measure things. And have to generate our own Spice models. In
    the case of this new fet, it's arguably a depletion fet and there is
    no Idss specified. They basicaly say, bias it until it works.

    That's crazy.



    If it works it works, I have done spice simulation that told me things did not work that I used for many years
    without problems...
    Spice may be nice for complex filters etc, but there are better programs for that
    the rest really needs just hands on experience and UNDERSTANDING about how them electrons like to move.
    And the time factor, test maybe be an afternoon and even bending a PCB trace makes lot of difference,
    spice you can do for weeks, have then nothing you can be sure about that works :-)
    Imagine WW3 and you only have a hand full of BC547 or something that survived the EMP and now you need to build that radio
    No spice bummer...
    No problem for me.


    Just more work for everyone.

    They probably support people who will buy millions.



    --

    I yam what I yam - Popeye

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Fri Mar 4 06:48:32 2022
    On Thu, 3 Mar 2022 17:43:15 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn wrote:
    On Thu, 03 Mar 2022 13:13:01 -0800, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:

    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de> >>>>>>>>>> wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >>>>>>>>>> the basic electrical properties of the part. Maybe it's like "load >>>>>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >>>>>>>> they emphasize analytical, necessarily linear, ideas like s-params and >>>>>>>> Smith charts. Things that could be sort-of handled with pencils and >>>>>>>> slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically
    tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are >>>>>> used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    A few competitors will spend big bucks to measure the enemies parts,
    and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs
    until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Yes, but they *do* have them.

    You know this how, exactly?

    Actually, much of what they make is better simulated using a full EM
    field solver, which spice cannot touch.

    SPICE is a pretty capable package for solving sparse systems of
    nonlinear ODEs, with a few features bolted on for other things such as >transmission lines. (A transmission line has invisible internal state,
    and so can't be simulated by ODEs.)

    It doesn't model carrier diffusion, which is probably its worst
    deficiency in high speed circuitry. Second worst is that its noise >simulation capability is very limited--it's just a linearized >propagation-of-errors calculation based on a single operating point. In >reality, many noise sources don't behave that way--for instance, shot
    noise depends on the instantaneous current, so noise correlations with
    signal can be far from negligible in real life.

    But most of those things aren't done any better by your average
    full-wave EM code, which has zero information about the circuit
    properties and probably couldn't do carrier dynamics to save its virtual >life, even if you gave it a physical description of the circuit with the >required spatial resolution everywhere. (This would not be your elegant >lightweight input file, you understand.)

    I wrote a clusterized optimizing FDTD code for my antenna-coupled MIM
    tunnel junction work about 15 years ago, so I have relevant experience.

    My guess is that if they published simplified spice models, they would
    get endless questions about this or that inaccuracy, so they avoid the
    expense by not issuing such models.

    Op amp makers have the inaccuracy problem in spades, which they handle
    by lying through their teeth AFAICT--they say that better models would
    reveal too much about their designs, or run too slowly, or put warts on >everybody's nose, or something.

    Cheers

    Phil Hobbs

    We should distinguish between a "Spice model" and a Spice program.

    This is a jfet model:

    .model 2N3819 NJF(Beta=1.304m Betatce=-.5 Rd=1 Rs=1 Lambda=2.25m
    Vto=-3 Vtotc=-2.5m Is=33.57f Isr=322.4f N=1 Nr=2 Xti=3 Alpha=311.7u
    Vk=243.6 Cgd=1.6p M=.3622 Pb=1 Fc=.5 Cgs=2.414p Kf=9.882E-18 Af=1
    mfg=Vishay)

    It assigns values in SI units to elements of device physics. That,
    plus some package parasitics and thermals, defines the device. That
    could be the input to LT Spice or to an expensive RF suite or to 12
    professors with slide rules.

    But the values are there. Narrowband load pull measurements are
    different.

    Opamp models can be incomplete, but they are better than s-parameters.





    --

    I yam what I yam - Popeye

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From jlarkin@highlandsniptechnology.com@21:1/5 to pNaonStpealmtje@yahoo.com on Fri Mar 4 07:35:20 2022
    On Fri, 04 Mar 2022 15:20:45 GMT, Jan Panteltje
    <pNaonStpealmtje@yahoo.com> wrote:

    On a sunny day (Fri, 04 Mar 2022 06:36:25 -0800) it happened
    jlarkin@highlandsniptechnology.com wrote in ><nl842h59cjijh7s4op6fbvvgjlt7n54k03@4ax.com>:

    On Fri, 04 Mar 2022 08:41:25 GMT, Jan Panteltje
    <pNaonStpealmtje@yahoo.com> wrote:

    On a sunny day (Thu, 03 Mar 2022 13:13:01 -0800) it happened John Larkin >>><jlarkin@highland_atwork_technology.com> wrote in >>><sgb22hp17vp6tad22b0e900asqnpjikmqt@4ax.com>:

    Their data sheets should have a giant header that shouts

    FOR RF USE ONLY

    John, that is their market.

    They have defined it as such, so deliberately discouraged a large
    class of potential customers. That's weird.


    If you want to use your bike for mountain climbing you cannot demand all bike manufacturers to give specs for that.
    It is NOT that hard to make a test circuit and measure things, I do that with most new to me devices
    including Minicircuits (you actually gave me the idea to try some of their stuff (mixers)..)

    We do measure things. And have to generate our own Spice models. In
    the case of this new fet, it's arguably a depletion fet and there is
    no Idss specified. They basicaly say, bias it until it works.

    That's crazy.

    Well its nature:-)
    There may be / will be some production spread in the cut-off gate voltage, that is with all FETs.
    You could make a feedback loop..


    If it works it works, I have done spice simulation that told me things did not work that I used for many years
    without problems...
    Spice may be nice for complex filters etc, but there are better programs for that
    the rest really needs just hands on experience and UNDERSTANDING about how them electrons like to move.
    And the time factor, test maybe be an afternoon and even bending a PCB trace makes lot of difference,
    spice you can do for weeks, have then nothing you can be sure about that works :-)
    Imagine WW3 and you only have a hand full of BC547 or something that survived the EMP and now you need to build that radio
    No spice bummer...
    No problem for me.


    Just more work for everyone.

    But you need that test circuit and measurements anyway? I do.

    The first step is to select a part. I don't want to buy and test a
    hundred parts. Basic DC specs are fundamental.



    They probably support people who will buy millions.

    And it is also the fun of learning something new :-)
    Am working at version 0.5.1 of my FLIR software, things evolve.


    --

    I yam what I yam - Popeye

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jan Panteltje@21:1/5 to jlarkin@highlandsniptechnology.com on Fri Mar 4 15:20:45 2022
    On a sunny day (Fri, 04 Mar 2022 06:36:25 -0800) it happened jlarkin@highlandsniptechnology.com wrote in <nl842h59cjijh7s4op6fbvvgjlt7n54k03@4ax.com>:

    On Fri, 04 Mar 2022 08:41:25 GMT, Jan Panteltje
    <pNaonStpealmtje@yahoo.com> wrote:

    On a sunny day (Thu, 03 Mar 2022 13:13:01 -0800) it happened John Larkin >><jlarkin@highland_atwork_technology.com> wrote in >><sgb22hp17vp6tad22b0e900asqnpjikmqt@4ax.com>:

    Their data sheets should have a giant header that shouts

    FOR RF USE ONLY

    John, that is their market.

    They have defined it as such, so deliberately discouraged a large
    class of potential customers. That's weird.


    If you want to use your bike for mountain climbing you cannot demand all bike manufacturers to give specs for that.
    It is NOT that hard to make a test circuit and measure things, I do that with most new to me devices
    including Minicircuits (you actually gave me the idea to try some of their stuff (mixers)..)

    We do measure things. And have to generate our own Spice models. In
    the case of this new fet, it's arguably a depletion fet and there is
    no Idss specified. They basicaly say, bias it until it works.

    That's crazy.

    Well its nature:-)
    There may be / will be some production spread in the cut-off gate voltage, that is with all FETs.
    You could make a feedback loop..


    If it works it works, I have done spice simulation that told me things did not work that I used for many years
    without problems...
    Spice may be nice for complex filters etc, but there are better programs for that
    the rest really needs just hands on experience and UNDERSTANDING about how them electrons like to move.
    And the time factor, test maybe be an afternoon and even bending a PCB trace makes lot of difference,
    spice you can do for weeks, have then nothing you can be sure about that works :-)
    Imagine WW3 and you only have a hand full of BC547 or something that survived the EMP and now you need to build that radio
    No spice bummer...
    No problem for me.


    Just more work for everyone.

    But you need that test circuit and measurements anyway? I do.


    They probably support people who will buy millions.

    And it is also the fun of learning something new :-)
    Am working at version 0.5.1 of my FLIR software, things evolve.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Fri Mar 4 10:58:50 2022
    On Thu, 3 Mar 2022 17:43:15 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn wrote:
    On Thu, 03 Mar 2022 13:13:01 -0800, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:

    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de> >>>>>>>>>> wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >>>>>>>>>> the basic electrical properties of the part. Maybe it's like "load >>>>>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >>>>>>>> they emphasize analytical, necessarily linear, ideas like s-params and >>>>>>>> Smith charts. Things that could be sort-of handled with pencils and >>>>>>>> slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically
    tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are >>>>>> used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    A few competitors will spend big bucks to measure the enemies parts,
    and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs
    until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Yes, but they *do* have them.

    You know this how, exactly?

    I've worked with a IC foundry for Gallium based analog RF components,
    and they do have full-accuracy models, which are closely held as trade
    secrets. I also recall comments by various SED denizens to the same
    effect.


    Actually, much of what they make is better simulated using a full EM
    field solver, which spice cannot touch.

    SPICE is a pretty capable package for solving sparse systems of
    nonlinear ODEs, with a few features bolted on for other things such as >transmission lines. (A transmission line has invisible internal state,
    and so can't be simulated by ODEs.)

    It doesn't model carrier diffusion, which is probably its worst
    deficiency in high speed circuitry. Second worst is that its noise >simulation capability is very limited--it's just a linearized >propagation-of-errors calculation based on a single operating point. In >reality, many noise sources don't behave that way--for instance, shot
    noise depends on the instantaneous current, so noise correlations with
    signal can be far from negligible in real life.

    But most of those things aren't done any better by your average
    full-wave EM code, which has zero information about the circuit
    properties and probably couldn't do carrier dynamics to save its virtual >life, even if you gave it a physical description of the circuit with the >required spatial resolution everywhere. (This would not be your elegant >lightweight input file, you understand.)

    I wrote a clusterized optimizing FDTD code for my antenna-coupled MIM
    tunnel junction work about 15 years ago, so I have relevant experience.

    Yes. The foundry design modeling systems are often bespoke, for
    precisely those reasons.

    As others have said, harmonic-balance simulators are widely used as
    well.

    Many use RF design systems from such as HP/Agilent. Some use COMSOL.


    My guess is that if they published simplified spice models, they would
    get endless questions about this or that inaccuracy, so they avoid the
    expense by not issuing such models.

    Op amp makers have the inaccuracy problem in spades, which they handle
    by lying through their teeth AFAICT--they say that better models would
    reveal too much about their designs, or run too slowly, or put warts on >everybody's nose, or something.

    Yes, these are excuses. But the problem is not technical.


    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to All on Fri Mar 4 10:02:58 2022
    On Fri, 4 Mar 2022 05:10:09 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 16:21 schrieb jlarkin@highlandsniptechnology.com:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
    On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    We talked about pin diode switches last week. Do you know
    the carrier lifetime of the diodes?

    It's usually on the data sheet. But V/I curves often aren't! That's
    crazy. So we have to measure that.


    Does Spice have any
    idea what that might be? And this is THE parameter that
    makes PIN diodes happen.

    Well, the DC curves matter too, if you want to inject carriers.


    And the voltage exactly when/where on a polysilicon gate.
    End, feed point, somewhere in between?

    If you know that, you know all the RF stuff. That doesn't work in
    reverse.

    What with noise calculations in a nonlinear environment?

    I've done that with Spice. I just add some noise generators and run a time-domain model.

    It would be more convenient if the noise models worked in time domain,
    but we can deal with that. We understand it.


    Try that with Spice in a chopper amplifier.

    Which operating point would you choose in the chopper
    amplifier? Switch at A or B? You must make up your mind;
    noise analysis has not the concept of time.

    It takes harmonic balance methods to do it.

    But they handle a very narrow group of cases.

    If you are saying that Spice is sometimes incomplete, we understand
    that and can adapt. But I still want to know if this is a depletion
    fet, and what Idss is.

    Most depletion phemts turn out to enhance usefully, or a lot. 2x Idss
    or 1/2 Rds-on can be useful. Nobody mentions that! Actually, I've
    never seen an Rds-on spec for a phemt... it's an RF part!

    But they can be dynamite RF switches, except that the RF boys don't
    seem to think about parts switching.


    Here's a model used by ADS:

    https://edadocs.software.keysight.com/pages/viewpage.action?pageId=6063379

    Those device parameters wouild be useful in Spice too. But RF part
    specs rarely reveal them.


    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to jlarkin@highlandsniptechnology.com on Fri Mar 4 14:00:20 2022
    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:43:15 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn wrote:
    On Thu, 03 Mar 2022 13:13:01 -0800, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:

    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >>>>>>>>>>> the basic electrical properties of the part. Maybe it's like "load >>>>>>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >>>>>>>>> they emphasize analytical, necessarily linear, ideas like s-params and
    Smith charts. Things that could be sort-of handled with pencils and >>>>>>>>> slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically
    tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are >>>>>>> used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    A few competitors will spend big bucks to measure the enemies parts,
    and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs >>>> until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Yes, but they *do* have them.

    You know this how, exactly?

    Actually, much of what they make is better simulated using a full EM
    field solver, which spice cannot touch.

    SPICE is a pretty capable package for solving sparse systems of
    nonlinear ODEs, with a few features bolted on for other things such as
    transmission lines. (A transmission line has invisible internal state,
    and so can't be simulated by ODEs.)

    It doesn't model carrier diffusion, which is probably its worst
    deficiency in high speed circuitry. Second worst is that its noise
    simulation capability is very limited--it's just a linearized
    propagation-of-errors calculation based on a single operating point. In
    reality, many noise sources don't behave that way--for instance, shot
    noise depends on the instantaneous current, so noise correlations with
    signal can be far from negligible in real life.

    But most of those things aren't done any better by your average
    full-wave EM code, which has zero information about the circuit
    properties and probably couldn't do carrier dynamics to save its virtual
    life, even if you gave it a physical description of the circuit with the
    required spatial resolution everywhere. (This would not be your elegant
    lightweight input file, you understand.)

    I wrote a clusterized optimizing FDTD code for my antenna-coupled MIM
    tunnel junction work about 15 years ago, so I have relevant experience.

    My guess is that if they published simplified spice models, they would
    get endless questions about this or that inaccuracy, so they avoid the
    expense by not issuing such models.

    Op amp makers have the inaccuracy problem in spades, which they handle
    by lying through their teeth AFAICT--they say that better models would
    reveal too much about their designs, or run too slowly, or put warts on
    everybody's nose, or something.

    Cheers

    Phil Hobbs

    We should distinguish between a "Spice model" and a Spice program.

    This is a jfet model:

    .model 2N3819 NJF(Beta=1.304m Betatce=-.5 Rd=1 Rs=1 Lambda=2.25m
    Vto=-3 Vtotc=-2.5m Is=33.57f Isr=322.4f N=1 Nr=2 Xti=3 Alpha=311.7u
    Vk=243.6 Cgd=1.6p M=.3622 Pb=1 Fc=.5 Cgs=2.414p Kf=9.882E-18 Af=1
    mfg=Vishay)

    It assigns values in SI units to elements of device physics. That,
    plus some package parasitics and thermals, defines the device. That
    could be the input to LT Spice or to an expensive RF suite or to 12 professors with slide rules.

    But the values are there. Narrowband load pull measurements are
    different.

    Spice models only include things that Spice understands, though.
    Carrier lifetime, diffusion behaviour, doping profiles and so on aren't
    in there. (The diode model does have the voltage-variable capacitance,
    but AIUI it's basically behavioural--it sure doesn't model forward
    recovery.)

    Opamp models can be incomplete, but they are better than s-parameters.

    Assuming they're reasonably accurate. The s-parameters are probably
    correct at one bias point at least. ;)

    Cheers

    Phil Hobbs


    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Joe Gwinn on Fri Mar 4 14:01:33 2022
    Joe Gwinn wrote:
    On Thu, 3 Mar 2022 17:43:15 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn wrote:
    On Thu, 03 Mar 2022 13:13:01 -0800, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:

    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know >>>>>>>>>>> the basic electrical properties of the part. Maybe it's like "load >>>>>>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >>>>>>>>> they emphasize analytical, necessarily linear, ideas like s-params and
    Smith charts. Things that could be sort-of handled with pencils and >>>>>>>>> slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically
    tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are >>>>>>> used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    A few competitors will spend big bucks to measure the enemies parts,
    and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs >>>> until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Yes, but they *do* have them.

    You know this how, exactly?

    I've worked with a IC foundry for Gallium based analog RF components,
    and they do have full-accuracy models, which are closely held as trade secrets. I also recall comments by various SED denizens to the same
    effect.


    Actually, much of what they make is better simulated using a full EM
    field solver, which spice cannot touch.

    SPICE is a pretty capable package for solving sparse systems of
    nonlinear ODEs, with a few features bolted on for other things such as
    transmission lines. (A transmission line has invisible internal state,
    and so can't be simulated by ODEs.)

    It doesn't model carrier diffusion, which is probably its worst
    deficiency in high speed circuitry. Second worst is that its noise
    simulation capability is very limited--it's just a linearized
    propagation-of-errors calculation based on a single operating point. In
    reality, many noise sources don't behave that way--for instance, shot
    noise depends on the instantaneous current, so noise correlations with
    signal can be far from negligible in real life.

    But most of those things aren't done any better by your average
    full-wave EM code, which has zero information about the circuit
    properties and probably couldn't do carrier dynamics to save its virtual
    life, even if you gave it a physical description of the circuit with the
    required spatial resolution everywhere. (This would not be your elegant
    lightweight input file, you understand.)

    I wrote a clusterized optimizing FDTD code for my antenna-coupled MIM
    tunnel junction work about 15 years ago, so I have relevant experience.

    Yes. The foundry design modeling systems are often bespoke, for
    precisely those reasons.

    As others have said, harmonic-balance simulators are widely used as
    well.

    Many use RF design systems from such as HP/Agilent. Some use COMSOL.


    My guess is that if they published simplified spice models, they would
    get endless questions about this or that inaccuracy, so they avoid the
    expense by not issuing such models.

    Op amp makers have the inaccuracy problem in spades, which they handle
    by lying through their teeth AFAICT--they say that better models would
    reveal too much about their designs, or run too slowly, or put warts on
    everybody's nose, or something.

    Yes, these are excuses. But the problem is not technical.


    Have you actually done any of that stuff yourself?

    Cheers

    Phil Hobbs


    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Fri Mar 4 11:09:54 2022
    On Fri, 4 Mar 2022 14:00:20 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:43:15 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn wrote:
    On Thu, 03 Mar 2022 13:13:01 -0800, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:

    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joegwinn@comcast.net> >>>>> wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote: >>>>>>>>>> On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>>>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know
    the basic electrical properties of the part. Maybe it's like "load >>>>>>>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >>>>>>>>>> they emphasize analytical, necessarily linear, ideas like s-params and
    Smith charts. Things that could be sort-of handled with pencils and >>>>>>>>>> slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically >>>>>> tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are >>>>>>>> used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    A few competitors will spend big bucks to measure the enemies parts, >>>>> and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs >>>>> until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Yes, but they *do* have them.

    You know this how, exactly?

    Actually, much of what they make is better simulated using a full EM
    field solver, which spice cannot touch.

    SPICE is a pretty capable package for solving sparse systems of
    nonlinear ODEs, with a few features bolted on for other things such as
    transmission lines. (A transmission line has invisible internal state,
    and so can't be simulated by ODEs.)

    It doesn't model carrier diffusion, which is probably its worst
    deficiency in high speed circuitry. Second worst is that its noise
    simulation capability is very limited--it's just a linearized
    propagation-of-errors calculation based on a single operating point. In >>> reality, many noise sources don't behave that way--for instance, shot
    noise depends on the instantaneous current, so noise correlations with
    signal can be far from negligible in real life.

    But most of those things aren't done any better by your average
    full-wave EM code, which has zero information about the circuit
    properties and probably couldn't do carrier dynamics to save its virtual >>> life, even if you gave it a physical description of the circuit with the >>> required spatial resolution everywhere. (This would not be your elegant >>> lightweight input file, you understand.)

    I wrote a clusterized optimizing FDTD code for my antenna-coupled MIM
    tunnel junction work about 15 years ago, so I have relevant experience.

    My guess is that if they published simplified spice models, they would >>>> get endless questions about this or that inaccuracy, so they avoid the >>>> expense by not issuing such models.

    Op amp makers have the inaccuracy problem in spades, which they handle
    by lying through their teeth AFAICT--they say that better models would
    reveal too much about their designs, or run too slowly, or put warts on
    everybody's nose, or something.

    Cheers

    Phil Hobbs

    We should distinguish between a "Spice model" and a Spice program.

    This is a jfet model:

    .model 2N3819 NJF(Beta=1.304m Betatce=-.5 Rd=1 Rs=1 Lambda=2.25m
    Vto=-3 Vtotc=-2.5m Is=33.57f Isr=322.4f N=1 Nr=2 Xti=3 Alpha=311.7u
    Vk=243.6 Cgd=1.6p M=.3622 Pb=1 Fc=.5 Cgs=2.414p Kf=9.882E-18 Af=1
    mfg=Vishay)

    It assigns values in SI units to elements of device physics. That,
    plus some package parasitics and thermals, defines the device. That
    could be the input to LT Spice or to an expensive RF suite or to 12
    professors with slide rules.

    But the values are there. Narrowband load pull measurements are
    different.

    Spice models only include things that Spice understands, though.
    Carrier lifetime, diffusion behaviour, doping profiles and so on aren't
    in there. (The diode model does have the voltage-variable capacitance,
    but AIUI it's basically behavioural--it sure doesn't model forward
    recovery.)

    Sure. And we understand that.

    I don't know much about the big RF suites. Can they model pin diodes
    and srds and such? Can they model the time-domain switching behavior
    of a pin diode switch?


    Opamp models can be incomplete, but they are better than s-parameters.

    Assuming they're reasonably accurate. The s-parameters are probably
    correct at one bias point at least. ;)

    We're using THS4302s, which do have s-params. But they also have DC
    specs and capacitances and pulse shots and slew rates. Best of both
    worlds.

    --

    If a man will begin with certainties, he shall end with doubts,
    but if he will be content to begin with doubts he shall end in certainties. Francis Bacon

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Fri Mar 4 14:30:41 2022
    On Fri, 4 Mar 2022 14:01:33 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn wrote:
    On Thu, 3 Mar 2022 17:43:15 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn wrote:
    On Thu, 03 Mar 2022 13:13:01 -0800, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:

    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joegwinn@comcast.net> >>>>> wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote: >>>>>>>>>> On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly.

    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages.
    What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF >>>>>>>>>>>> comes out."

    I wonder how people generate those "design kits" if they don't know
    the basic electrical properties of the part. Maybe it's like "load >>>>>>>>>>>> pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so >>>>>>>>>> they emphasize analytical, necessarily linear, ideas like s-params and
    Smith charts. Things that could be sort-of handled with pencils and >>>>>>>>>> slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically >>>>>> tractable theory that was also useful.


    That's because non-linearities are avoided like the plague.
    They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are >>>>>>>> used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    A few competitors will spend big bucks to measure the enemies parts, >>>>> and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs >>>>> until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Yes, but they *do* have them.

    You know this how, exactly?

    I've worked with a IC foundry for Gallium based analog RF components,
    and they do have full-accuracy models, which are closely held as trade
    secrets. I also recall comments by various SED denizens to the same
    effect.


    Actually, much of what they make is better simulated using a full EM
    field solver, which spice cannot touch.

    SPICE is a pretty capable package for solving sparse systems of
    nonlinear ODEs, with a few features bolted on for other things such as
    transmission lines. (A transmission line has invisible internal state,
    and so can't be simulated by ODEs.)

    It doesn't model carrier diffusion, which is probably its worst
    deficiency in high speed circuitry. Second worst is that its noise
    simulation capability is very limited--it's just a linearized
    propagation-of-errors calculation based on a single operating point. In >>> reality, many noise sources don't behave that way--for instance, shot
    noise depends on the instantaneous current, so noise correlations with
    signal can be far from negligible in real life.

    But most of those things aren't done any better by your average
    full-wave EM code, which has zero information about the circuit
    properties and probably couldn't do carrier dynamics to save its virtual >>> life, even if you gave it a physical description of the circuit with the >>> required spatial resolution everywhere. (This would not be your elegant >>> lightweight input file, you understand.)

    I wrote a clusterized optimizing FDTD code for my antenna-coupled MIM
    tunnel junction work about 15 years ago, so I have relevant experience.

    Yes. The foundry design modeling systems are often bespoke, for
    precisely those reasons.

    As others have said, harmonic-balance simulators are widely used as
    well.

    Many use RF design systems from such as HP/Agilent. Some use COMSOL.


    My guess is that if they published simplified spice models, they would >>>> get endless questions about this or that inaccuracy, so they avoid the >>>> expense by not issuing such models.

    Op amp makers have the inaccuracy problem in spades, which they handle
    by lying through their teeth AFAICT--they say that better models would
    reveal too much about their designs, or run too slowly, or put warts on
    everybody's nose, or something.

    Yes, these are excuses. But the problem is not technical.


    Have you actually done any of that stuff yourself?

    No, I have not. But I have worked with people who have and still do
    such modeling and have seen their analyses.

    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to jlarkin@highland_atwork_technology. on Fri Mar 4 14:38:25 2022
    On Fri, 04 Mar 2022 11:09:54 -0800, John Larkin <jlarkin@highland_atwork_technology.com> wrote:

    On Fri, 4 Mar 2022 14:00:20 -0500, Phil Hobbs ><pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:43:15 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn wrote:
    On Thu, 03 Mar 2022 13:13:01 -0800, John Larkin
    <jlarkin@highland_atwork_technology.com> wrote:

    On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joegwinn@comcast.net> >>>>>> wrote:

    On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
    <spamjunk@blueyonder.co.uk> wrote:

    On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote: >>>>>>>>>>> On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    jlarkin@highlandsniptechnology.com wrote:
    On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
    wrote:

    Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com: >>>>>>>>>>>>>>> On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
    <richsulinengineer@gmail.com> wrote:

    Those loadpull charts on page 5 are a mess,
    unreadable, If this is what its like, then
    No wonder a lot of RF guys retire unexpectedly. >>>>>>>>>>>>>>>
    RF lives in the dark ages. We need Spice models.

    Don't mke me laugh so hard. Spice IS the dark ages. >>>>>>>>>>>>>> What we need is AWR or ADS design kits.

    Gerhard

    What's wrong with knowing all the voltages and currents as a function
    of time?

    If you know that, you know all the RF stuff. That doesn't work in >>>>>>>>>>>>> reverse.

    And what's wrong with knowing drain current as a function of gate >>>>>>>>>>>>> voltage? RF data sheets usually say "turn the trimpot until the RF
    comes out."

    I wonder how people generate those "design kits" if they don't know
    the basic electrical properties of the part. Maybe it's like "load
    pull" engineering.


    They probably make about eight of them over the lifetime of the part, so
    statistics are hard to come by. ;)

    Cheers

    Phil Hobbs

    Rf is a strange world. I think its traditions pre-date computers, so
    they emphasize analytical, necessarily linear, ideas like s-params and
    Smith charts. Things that could be sort-of handled with pencils and >>>>>>>>>>> slide rules.

    Yes. Well before computers. And the key was finding the right
    mathematical and physical approximations, yielding an analytically >>>>>>> tractable theory that was also useful.


    That's because non-linearities are avoided like the plague. >>>>>>>>>> They cause harmonics that screw you /and other/ users up.

    So wouldn't you want a Spice model to evaluate that? Not all parts are
    used small-signal.

    Well, the device manufacturers do have such models, but the
    manufacturers do not release anything that revealing, to avoid
    educating their competitors.


    A few competitors will spend big bucks to measure the enemies parts, >>>>>> and they have the facilities to do it. So why should a thousand
    end-users have to do the measurements themselves, or spin product revs >>>>>> until it works?

    I asked MiniCircuits for Spice models of their phemts. They were
    adamant, agressive even, that they will NEVER have Spice models.

    Yes, but they *do* have them.

    You know this how, exactly?

    Actually, much of what they make is better simulated using a full EM >>>>> field solver, which spice cannot touch.

    SPICE is a pretty capable package for solving sparse systems of
    nonlinear ODEs, with a few features bolted on for other things such as >>>> transmission lines. (A transmission line has invisible internal state, >>>> and so can't be simulated by ODEs.)

    It doesn't model carrier diffusion, which is probably its worst
    deficiency in high speed circuitry. Second worst is that its noise
    simulation capability is very limited--it's just a linearized
    propagation-of-errors calculation based on a single operating point. In >>>> reality, many noise sources don't behave that way--for instance, shot
    noise depends on the instantaneous current, so noise correlations with >>>> signal can be far from negligible in real life.

    But most of those things aren't done any better by your average
    full-wave EM code, which has zero information about the circuit
    properties and probably couldn't do carrier dynamics to save its virtual >>>> life, even if you gave it a physical description of the circuit with the >>>> required spatial resolution everywhere. (This would not be your elegant >>>> lightweight input file, you understand.)

    I wrote a clusterized optimizing FDTD code for my antenna-coupled MIM
    tunnel junction work about 15 years ago, so I have relevant experience. >>>>
    My guess is that if they published simplified spice models, they would >>>>> get endless questions about this or that inaccuracy, so they avoid the >>>>> expense by not issuing such models.

    Op amp makers have the inaccuracy problem in spades, which they handle >>>> by lying through their teeth AFAICT--they say that better models would >>>> reveal too much about their designs, or run too slowly, or put warts on >>>> everybody's nose, or something.

    Cheers

    Phil Hobbs

    We should distinguish between a "Spice model" and a Spice program.

    This is a jfet model:

    .model 2N3819 NJF(Beta=1.304m Betatce=-.5 Rd=1 Rs=1 Lambda=2.25m
    Vto=-3 Vtotc=-2.5m Is=33.57f Isr=322.4f N=1 Nr=2 Xti=3 Alpha=311.7u
    Vk=243.6 Cgd=1.6p M=.3622 Pb=1 Fc=.5 Cgs=2.414p Kf=9.882E-18 Af=1
    mfg=Vishay)

    It assigns values in SI units to elements of device physics. That,
    plus some package parasitics and thermals, defines the device. That
    could be the input to LT Spice or to an expensive RF suite or to 12
    professors with slide rules.

    But the values are there. Narrowband load pull measurements are
    different.

    Spice models only include things that Spice understands, though.
    Carrier lifetime, diffusion behaviour, doping profiles and so on aren't
    in there. (The diode model does have the voltage-variable capacitance,
    but AIUI it's basically behavioural--it sure doesn't model forward >>recovery.)

    Sure. And we understand that.

    I don't know much about the big RF suites. Can they model pin diodes
    and srds and such? Can they model the time-domain switching behavior
    of a pin diode switch?

    PIN Diodes, yes - I see that all the time.

    SRDs - not very well.

    The big practical problem with SRDs is jitter inherent to the device
    physics. The jitter causes lots of phase noise. For low phase noise
    comb generators (used for frequency multiplication) people have gone
    to nonlinear transmission lines, such as those made by MACom, despite
    the component cost.

    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From whit3rd@21:1/5 to jla...@highlandsniptechnology.com on Fri Mar 4 14:22:49 2022
    On Friday, March 4, 2022 at 6:48:45 AM UTC-8, jla...@highlandsniptechnology.com wrote:

    We should distinguish between a "Spice model" and a Spice program.

    This is a jfet model:

    .model 2N3819 NJF(Beta=1.304m Betatce=-.5 Rd=1 Rs=1 Lambda=2.25m
    Vto=-3 Vtotc=-2.5m Is=33.57f Isr=322.4f N=1 Nr=2 Xti=3 Alpha=311.7u
    Vk=243.6 Cgd=1.6p M=.3622 Pb=1 Fc=.5 Cgs=2.414p Kf=9.882E-18 Af=1
    mfg=Vishay)

    It assigns values in SI units to elements of device physics.

    Which is to say, it fills in parameters for a built-in SPICE model, designated NJF,
    that is documented somewhere... older SPICE variants had J2N3819-named models for JFETs.
    I wouldn't designate that text 'a model', rather I'd call it a 'model statement' for the particular
    SPICE variant in use.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Skittles@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Tue Mar 8 09:10:22 2022
    On Wed, 2 Mar 2022 18:41:23 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Hobbs wrote:
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?


    It does specify the threshold as -1.5 to -3.5V, but doesn't give the
    corresponding I_D.

    Nice package--wonder if it comes in DIP? ;)

    (Almost certainly way too rich for my blood, if it's intended for cell
    tower use, but an interesting part, for sure.)

    BTW: they're specifying the output power at *3 dB compression*. Who
    ever heard of that?

    Cheers

    Phil Hobbs


    If you are designing Doherties then it is very relevant.


    Skittles

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Skittles on Tue Mar 8 11:28:58 2022
    Skittles wrote:
    On Wed, 2 Mar 2022 18:41:23 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Hobbs wrote:
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull.

    I suspect it's a depletion fet. Idss? What's that?


    It does specify the threshold as -1.5 to -3.5V, but doesn't give the
    corresponding I_D.

    Nice package--wonder if it comes in DIP? ;)

    (Almost certainly way too rich for my blood, if it's intended for cell
    tower use, but an interesting part, for sure.)

    BTW: they're specifying the output power at *3 dB compression*. Who
    ever heard of that?


    If you are designing Doherties then it is very relevant.


    Skittles


    So are you the "beer & skittles" kind or the kid candy kind?

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
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  • From Skittles@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Tue Mar 8 20:56:30 2022
    On Tue, 8 Mar 2022 11:28:58 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Skittles wrote:
    On Wed, 2 Mar 2022 18:41:23 -0500, Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Phil Hobbs wrote:
    John Larkin wrote:
    https://www.galliumsemi.com/products-1/gt010d

    This being an RF part, there are no DC or capacitance specs. This
    being a power part, there are no S-parms. All you get are load pull. >>>>>
    I suspect it's a depletion fet. Idss? What's that?


    It does specify the threshold as -1.5 to -3.5V, but doesn't give the
    corresponding I_D.

    Nice package--wonder if it comes in DIP? ;)

    (Almost certainly way too rich for my blood, if it's intended for cell >>>> tower use, but an interesting part, for sure.)

    BTW: they're specifying the output power at *3 dB compression*. Who
    ever heard of that?


    If you are designing Doherties then it is very relevant.


    Skittles


    So are you the "beer & skittles" kind or the kid candy kind?

    Cheers

    Phil Hobbs


    Definitely beer and skittles.

    Tally Ho!

    Skittles

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