There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell from
the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
On Sun, 02 Jun 2024 15:36:35 -0700, john larkin wrote:
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell from
the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
Define "fast".
"john larkin" <jl@650pot.com> wrote in message news:eqsp5jde87vqs6du4a7djoalag7kpkuhkr@4ax.com...
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
I want to make a model of the MC10EP89 gate.
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message news:eqsp5jde87vqs6du4a7djoalag7kpkuhkr@4ax.com...
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message news:eqsp5jde87vqs6du4a7djoalag7kpkuhkr@4ax.com...
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
"john larkin" <jl@650pot.com> wrote in message news:4n2q5jln0sb9oqbfp81jm723tbjf7tol80@4ax.com...
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message news:eqsp5jde87vqs6du4a7djoalag7kpkuhkr@4ax.com...
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part number could be included.
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message
news:4n2q5jln0sb9oqbfp81jm723tbjf7tol80@4ax.com...
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message
news:eqsp5jde87vqs6du4a7djoalag7kpkuhkr@4ax.com...
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part
number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message news:4n2q5jln0sb9oqbfp81jm723tbjf7tol80@4ax.com...
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message news:eqsp5jde87vqs6du4a7djoalag7kpkuhkr@4ax.com...
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
john larkin <jl@650pot.com> wrote:
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message
news:4n2q5jln0sb9oqbfp81jm723tbjf7tol80@4ax.com...
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message
news:eqsp5jde87vqs6du4a7djoalag7kpkuhkr@4ax.com...
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell >>>>>> from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part
number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Ft isn’t one of the model parameters, guess you have to look for low Tf and >Tr transit times or low junction capacitances?
On Mon, 3 Jun 2024 17:18:15 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 3/06/2024 1:22 pm, john larkin wrote:
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message news:4n2q5jln0sb9oqbfp81jm723tbjf7tol80@4ax.com...
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message news:eqsp5jde87vqs6du4a7djoalag7kpkuhkr@4ax.com...
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell >>>>>>> from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Here's a circuit that includes a 5GHz ft BFR92A, which a typical
broad-band transistor. I had to put in the Spice model into the .asc
file myself.
There used to be quite a few of them around, but - as Phil Hobbs has
mentioned - most of them have gone obsolete. He has tracked down a
surviving PNP equivalent, but you won't need that to simulate ECL.
It's not the first time I've posted such a .asc file here.
Gosh, what a hideous mess, in many respects.
On 3/06/2024 1:22 pm, john larkin wrote:
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message news:4n2q5jln0sb9oqbfp81jm723tbjf7tol80@4ax.com...
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message news:eqsp5jde87vqs6du4a7djoalag7kpkuhkr@4ax.com...
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell >>>>>> from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Here's a circuit that includes a 5GHz ft BFR92A, which a typical
broad-band transistor. I had to put in the Spice model into the .asc
file myself.
There used to be quite a few of them around, but - as Phil Hobbs has >mentioned - most of them have gone obsolete. He has tracked down a
surviving PNP equivalent, but you won't need that to simulate ECL.
It's not the first time I've posted such a .asc file here.
Version 4
SHEET 1 2924 1040
WIRE 128 -720 -768 -720
WIRE 304 -720 128 -720
WIRE 656 -720 304 -720
WIRE 1088 -720 656 -720
WIRE 1376 -720 1088 -720
WIRE 1584 -720 1376 -720
WIRE 1088 -576 1088 -720
WIRE 1376 -576 1376 -720
WIRE 128 -560 128 -720
WIRE 304 -560 304 -720
WIRE 656 -560 656 -720
WIRE 1584 -544 1584 -720
WIRE 1088 -400 1088 -496
WIRE 1088 -400 960 -400
WIRE 1248 -400 1088 -400
WIRE 960 -368 960 -400
WIRE 1248 -352 1248 -400
WIRE 656 -320 656 -480
WIRE 896 -320 656 -320
WIRE 1376 -304 1376 -496
WIRE 1376 -304 1312 -304
WIRE 128 -288 128 -480
WIRE 176 -288 128 -288
WIRE 304 -288 304 -480
WIRE 304 -288 240 -288
WIRE 656 -208 656 -320
WIRE 1376 -192 1376 -304
WIRE 1584 -192 1584 -480
WIRE 1584 -192 1376 -192
WIRE 304 -160 304 -288
WIRE 448 -160 304 -160
WIRE 592 -160 448 -160
WIRE -768 -64 -768 -720
WIRE 128 48 128 -288
WIRE 1376 48 1376 -192
WIRE -272 96 -432 96
WIRE 64 96 -192 96
WIRE 304 160 304 -160
WIRE 448 176 448 -160
WIRE -432 240 -432 96
WIRE -768 416 -768 16
WIRE -768 416 -880 416
WIRE -736 416 -768 416
WIRE -432 416 -432 320
WIRE -432 416 -736 416
WIRE 304 416 304 240
WIRE 304 416 -432 416
WIRE 960 416 960 -272
WIRE 960 416 304 416
WIRE 1376 416 1376 128
WIRE 1376 416 960 416
WIRE 1424 416 1376 416
WIRE 1520 416 1424 416
WIRE 128 464 128 144
WIRE 656 464 656 -112
WIRE 656 464 128 464
WIRE 1424 480 1424 416
WIRE -880 496 -880 416
WIRE 656 496 656 464
WIRE 1248 624 1248 -256
WIRE 1296 624 1248 624
WIRE 1424 624 1424 560
WIRE 1424 624 1296 624
WIRE -736 640 -736 416
WIRE -736 656 -736 640
WIRE 1424 688 1424 624
WIRE -736 944 -736 720
WIRE 448 944 448 256
WIRE 448 944 -736 944
WIRE 656 944 656 576
WIRE 656 944 448 944
WIRE 1424 944 1424 768
WIRE 1424 944 656 944
WIRE 1648 944 1424 944
FLAG -880 496 0
FLAG 1296 624 out
SYMBOL npn 64 48 R0
SYMATTR InstName Q1
SYMATTR Value BFR92A
SYMBOL npn 592 -208 R0
SYMATTR InstName Q2
SYMATTR Value BFR92A
SYMBOL voltage -768 -80 R0
WINDOW 123 0 0 Left 0
WINDOW 39 24 44 Left 2
SYMATTR SpiceLine Rser=0.1
SYMATTR InstName V1
SYMATTR Value 15.0
SYMBOL voltage -736 624 R0
WINDOW 123 0 0 Left 0
WINDOW 39 24 44 Left 2
SYMATTR SpiceLine Rser=0.1
SYMATTR InstName V2
SYMATTR Value 15.0
SYMBOL voltage -432 224 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(0 .2 1n 300p 300p 100p 100n 2)
SYMBOL res -176 80 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 27
SYMBOL res 640 480 R0
SYMATTR InstName R3
SYMATTR Value 3k0
SYMBOL res 112 -576 R0
SYMATTR InstName R4
SYMATTR Value 2k
SYMBOL res 288 144 R0
SYMATTR InstName R5
SYMATTR Value 100
SYMBOL res 640 -576 R0
SYMATTR InstName R6
SYMATTR Value 1k
SYMBOL res 288 -576 R0
SYMATTR InstName R2
SYMATTR Value 5k
SYMBOL cap 240 -304 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C1
SYMATTR Value 10p
SYMBOL res 432 160 R0
SYMATTR InstName R7
SYMATTR Value 7k5
SYMBOL pnp 1312 -256 R180
SYMATTR InstName Q3
SYMATTR Value 2N3906
SYMBOL pnp 896 -272 M180
SYMATTR InstName Q4
SYMATTR Value 2N3906
SYMBOL res 1072 -592 R0
SYMATTR InstName R8
SYMATTR Value 100
SYMBOL res 1360 -592 R0
SYMATTR InstName R9
SYMATTR Value 3k3
SYMBOL res 1360 32 R0
SYMATTR InstName R10
SYMATTR Value 12k
SYMBOL res 1408 464 R0
SYMATTR InstName R11
SYMATTR Value 56
SYMBOL res 1408 672 R0
SYMATTR InstName R12
SYMATTR Value 360
SYMBOL cap 1568 -544 R0
SYMATTR InstName C2
SYMATTR Value 10n
TEXT -272 1000 Left 2 !.model BFR92A NPN(IS=0.1213E-15 VAF=30 BF=94.73 >IKF=0.46227 XTB=0 BR=10.729 CJC=946.47E-15 CJE=10.416E-15 TR=1.2744E-9 >TF=26.796E-12 ITF=0.0044601 VTF=0.32861 XTF=0.3817 RB=14.998
RC=0.13793 RE=0.29088 Vceo=15 Icrating=4m mfg=Infineon)
TEXT -904 1024 Left 2 !.tran 0 300n 0
On 6/3/24 00:36, john larkin wrote:
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
I always used the -now obsolete- BFR92A for such things.
That's a 5GHz Ft NPN that I used often. It's not in the
library, I think. Below the model. Mind the line wraps.
Jeroen Belleman
.model BFR92A NPN IS=4.11877E-016 BF=1.02639E+002 NF=9.97275E-001 >VAF=6.26719E+001 IKF=3.20054E+000 ISE=4.01062E-015 NE=1.57708E+000 >BR=1.81086E+001 NR=9.96202E-001 VAR=3.36915E+000 IKR=1.28155E+000 >ISC=2.79905E-016 NC=1.07543E+000 RB=1.00000E+001 IRB=1.00000E-006 >RBM=1.00000E+001 RE=1.16450E+000 RC=2.32000E+000 EG=1.11000E+000 >XTI=3.00000E+000 CJE=8.90512E-013 VJE=6.00000E-001 MJE=2.58570E-001 >TF=1.54973E-011 XTF=3.91402E+001 VTF=2.15279E+000 ITF=2.13776E-001 >CJC=5.46563E-013 VJC=3.80824E-001 MJC=2.02935E-001
john larkin <jl@650pot.com> wrote:
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message
news:4n2q5jln0sb9oqbfp81jm723tbjf7tol80@4ax.com...
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message
news:eqsp5jde87vqs6du4a7djoalag7kpkuhkr@4ax.com...
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell >>>>>> from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part
number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Ft isn’t one of the model parameters, guess you have to look for low Tf and Tr transit times or low junction capacitances?
On Mon, 3 Jun 2024 07:50:37 -0000 (UTC), piglet
<erichpwagner@hotmail.com> wrote:
john larkin <jl@650pot.com> wrote:Agreed, but reading hundreds of lines of fine print, or looking up
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message
news:4n2q5jln0sb9oqbfp81jm723tbjf7tol80@4ax.com...
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message
news:eqsp5jde87vqs6du4a7djoalag7kpkuhkr@4ax.com...
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell >>>>>>> from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part
number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Ft isn’t one of the model parameters, guess you have to look for low Tf and
Tr transit times or low junction capacitances >
hundreds of data sheets, is a nuisance.
I sorted on lowest Vce and then found the capacitances and then looked
up the data sheets. LT Spice is not friendly to people with bad
vision.
I should have used one of the LS3xx parts. They have Vceo and Ic both
= 0.
On Mon, 3 Jun 2024 09:58:52 +0200, Jeroen Belleman
<jeroen@nospam.please> wrote:
On 6/3/24 00:36, john larkin wrote:
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
I always used the -now obsolete- BFR92A for such things.
That's a 5GHz Ft NPN that I used often. It's not in the
library, I think. Below the model. Mind the line wraps.
Jeroen Belleman
.model BFR92A NPN IS=4.11877E-016 BF=1.02639E+002 NF=9.97275E-001
VAF=6.26719E+001 IKF=3.20054E+000 ISE=4.01062E-015 NE=1.57708E+000
BR=1.81086E+001 NR=9.96202E-001 VAR=3.36915E+000 IKR=1.28155E+000
ISC=2.79905E-016 NC=1.07543E+000 RB=1.00000E+001 IRB=1.00000E-006
RBM=1.00000E+001 RE=1.16450E+000 RC=2.32000E+000 EG=1.11000E+000
XTI=3.00000E+000 CJE=8.90512E-013 VJE=6.00000E-001 MJE=2.58570E-001
TF=1.54973E-011 XTF=3.91402E+001 VTF=2.15279E+000 ITF=2.13776E-001
CJC=5.46563E-013 VJC=3.80824E-001 MJC=2.02935E-001
2SC3838K is in the library, and has Ft = 3.5G typically. It's good
enough for what I want to do now.
This is actually a bit faster than the MC10EP89:
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message news:4n2q5jln0sb9oqbfp81jm723tbjf7tol80@4ax.com...
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
"john larkin" <jl@650pot.com> wrote in message news:eqsp5jde87vqs6du4a7djoalag7kpkuhkr@4ax.com...
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Gosh, what a hideous mess, in many respects.
Do tell us why. You do claim to revel in electronic discussion.
On Tue, 4 Jun 2024 00:10:32 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
<snip>
Gosh, what a hideous mess, in many respects.
Do tell us why. You do claim to revel in electronic discussion.
Perhaps its the nonlinearity of the output stage, which is biased off.
So it's a switch, but the slow speed of the output, if engaged,
results in a stretched pulse.
The assertion that spice parameter Tf is related to spec sheet Ft is
only a guess.
The bfr92a model written into your simulation turns out to
be part of a more complete model published as a die-within-a-package.
There's little difference in performance when substituted into the simulation.
If all the models with Tf<20ps are evaluated, you get unpredictable
results. Note that the bfr92a model doesn't actually meet this
limitation, but other similar models do (~bfr93). There are roughly
270 of them.
Each will either:
- fail to engage with the slow output detector.(31)
- act roughly like the original simulation.(217)
- oscillate at an unrelated frequency.(19)
- stall.(1)
- give incoherent wild results (2)
http://ve3ute.ca/query/Tf_20ps_vs_bfr92a.zip
Just why one model does one thing, while another does something
else might be interesting to figure out.
On Tue, 4 Jun 2024 00:10:32 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
<snip>
Gosh, what a hideous mess, in many respects.
Do tell us why. You do claim to revel in electronic discussion.
Perhaps its the nonlinearity of the output stage, which is biased off.
On Wed, 05 Jun 2024 23:46:24 -0400, legg <legg@nospam.magma.ca> wrote:
On Tue, 4 Jun 2024 00:10:32 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
<snip>
Gosh, what a hideous mess, in many respects.
Do tell us why. You do claim to revel in electronic discussion.
Perhaps its the nonlinearity of the output stage, which is biased off.
I believe that a Spice model should be treated as an engineering
document: visible title, author, and correct latest-edit date, and it
should be neatly drawn, with coherent comments where appropriate. It
should be obvious where the inputs and outputs are, and important
nodes should have useful net names.
Versions should be identifiable as such.
A sim should be useful days or years after it's started. We often have
a README.txt file alongside the .asc files to explain the situation.
Most amateur Spice sims are messy tangled horrors.
On 6/06/2024 1:46 pm, legg wrote:<snip>
If all the models with Tf<20ps are evaluated, you get unpredictable
results. Note that the bfr92a model doesn't actually meet this
limitation, but other similar models do (~bfr93). There are roughly
270 of them.
Each will either:
- fail to engage with the slow output detector.(31)
If they aren't fast enough to get triggered as emitter-coupled
monostable by a pulse that is 400psec wide at hallf-maximium voltage
of 100mV.
- act roughly like the original simulation.(217)
- oscillate at an unrelated frequency.(19)
Broad-band transistors will oscillate without a base-stopper of adequate >resistance - I tended to end up with resistors between 22R and 33R.
There are better solutions, but in the work I did it wasn't worth the
trouble of finding them.
- stall.(1)
Up the gain.
- give incoherent wild results (2)
Change the base-stopper resistance.
http://ve3ute.ca/query/Tf_20ps_vs_bfr92a.zip
Just why one model does one thing, while another does something
else might be interesting to figure out.
No model is perfect. If you model something and it seems to work, it's
worth putting together a real circuit (which takes longer) and seeing
what it actually does.
If it doesn't work, or doesn't work all that well. fiddling with the
model may point the way to something that might work better.
--
Bill Sloman, Sydney
On Thu, 6 Jun 2024 23:18:12 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 6/06/2024 1:46 pm, legg wrote:
It's difficult to isolate a model parameter or product of parameters
that predict the performance demonstrated in this simulation.
Oscillators seem to have ( ~ mostly) high Rbb, which is
device-specific. . . . but also lower ( 1/100) IKR, which you'd
think was irrelevant.
Bf, Tr, Tf and capacitances don't stand out.
I suppose you'd need to look at the numbers separating astable from monostable operation. You wouldn't want an unspecified component
characteric to dominate basic circuit function.
On 7/06/2024 4:05 am, legg wrote:
On Thu, 6 Jun 2024 23:18:12 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 6/06/2024 1:46 pm, legg wrote:
<snip>
It's difficult to isolate a model parameter or product of parameters
that predict the performance demonstrated in this simulation.
Oscillators seem to have ( ~ mostly) high Rbb, which is
device-specific. . . . but also lower ( 1/100) IKR, which you'd
think was irrelevant.
Bf, Tr, Tf and capacitances don't stand out.
I suppose you'd need to look at the numbers separating astable from
monostable operation. You wouldn't want an unspecified component
characteric to dominate basic circuit function.
You don't get the choice, unless you are in the position of developing a
new transistor for a new market.
Most of us are in the position of finding a transistor which we can buy
- preferably off the shelf - which we can use to do a specific job.
The options tend to be pretty restricted. There are a lot fewer
broad-band transistors on the market than there used to be.
The manufacturer's Spice model give us the option of modelling a circuit >which might work in some version of Spice, and tweaking the circuit to
get the simulation to perform our job tolerably well.
We can't sell the simulation - customers want real circuits that work in
real life.
--
Bill Sloman, Sydney
On Fri, 7 Jun 2024 14:03:16 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 7/06/2024 4:05 am, legg wrote:
On Thu, 6 Jun 2024 23:18:12 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 6/06/2024 1:46 pm, legg wrote:
That's sort of what I'm talking about. You choose a part, you choose a
model, you choose a parameter that allows a model to simulate
performance more accurately. You choose a circuit configuration
with component values.
From the larger spreadsheet, you see models for 'similar devices
varying widely in performance in a particular circuit configuration.
So what is it, in the model, or in the circuit configuration, that
allows such a wide variation in performance. What parameter is a
true predictor? What weakness in the circuit is the wild card?
Looking for understanding or beneficial increase in knowledge here.
Not pushing or pulling the benefits or disadvantages of modeling
or breadboarding - already have pretty fixed opinions about that.
On 7/06/2024 11:24 pm, legg wrote:
On Fri, 7 Jun 2024 14:03:16 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 7/06/2024 4:05 am, legg wrote:
On Thu, 6 Jun 2024 23:18:12 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 6/06/2024 1:46 pm, legg wrote:
<snip>
That's sort of what I'm talking about. You choose a part, you choose a
model, you choose a parameter that allows a model to simulate
performance more accurately. You choose a circuit configuration
with component values.
You mostly can't chose an EBIC model because the manufacturers treat
them as "commercial in confidence".
Gummel-Poon isn't as good, but it's mostly adequate.
From the larger spreadsheet, you see models for 'similar devices
varying widely in performance in a particular circuit configuration.
So what is it, in the model, or in the circuit configuration, that
allows such a wide variation in performance. What parameter is a
true predictor? What weakness in the circuit is the wild card?
Silly question. Gummel-Poon doesn't model inverted bipolar transistor >operation particularly well, but if you want anything else you will have >measure the device parameters for yourself, and nobody here has ever
claimed to have done that.
Looking for understanding or beneficial increase in knowledge here.
Not pushing or pulling the benefits or disadvantages of modeling
or breadboarding - already have pretty fixed opinions about that.
Do try to understand what practical circuit designers actually do.
I've never seen anybody set up a "spreadsheet" of transistor models.
The process is mostly working out what you can do with what you can get.
The models aren't perfect, and individual devices aren't identical, so
coping with production variation is part of the job. Some parts are
sorted by the manufacturer after production, which gives you
funny-looking parameter distributions.
--
Bill Sloman, Sydney
On 7/06/2024 11:24 pm, legg wrote:
On Fri, 7 Jun 2024 14:03:16 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 7/06/2024 4:05 am, legg wrote:
On Thu, 6 Jun 2024 23:18:12 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 6/06/2024 1:46 pm, legg wrote:
<snip>
That's sort of what I'm talking about. You choose a part, you choose a
model, you choose a parameter that allows a model to simulate
performance more accurately. You choose a circuit configuration
with component values.
You mostly can't chose an EBIC model because the manufacturers treat
them as "commercial in confidence".
Gummel-Poon isn't as good, but it's mostly adequate.
From the larger spreadsheet, you see models for 'similar devices
varying widely in performance in a particular circuit configuration.
So what is it, in the model, or in the circuit configuration, that
allows such a wide variation in performance. What parameter is a
true predictor? What weakness in the circuit is the wild card?
Silly question. Gummel-Poon doesn't model inverted bipolar transistor >operation particularly well, but if you want anything else you will have >measure the device parameters for yourself, and nobody here has ever
claimed to have done that.
Looking for understanding or beneficial increase in knowledge here.
Not pushing or pulling the benefits or disadvantages of modeling
or breadboarding - already have pretty fixed opinions about that.
Do try to understand what practical circuit designers actually do.
I've never seen anybody set up a "spreadsheet" of transistor models.
The process is mostly working out what you can do with what you can get.
The models aren't perfect, and individual devices aren't identical, so
coping with production variation is part of the job. Some parts are
sorted by the manufacturer after production, which gives you
funny-looking parameter distributions.
--
Bill Sloman, Sydney
On Sat, 8 Jun 2024 03:29:11 +1000, Bill Sloman <bill.sloman@ieee.org><snip>
wrote:
On 7/06/2024 11:24 pm, legg wrote:
On Fri, 7 Jun 2024 14:03:16 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 7/06/2024 4:05 am, legg wrote:
On Thu, 6 Jun 2024 23:18:12 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>> wrote:
On 6/06/2024 1:46 pm, legg wrote
Right, I see Q2 normally inverted.
C2 seems unneccessarily loaded.
On 11/06/2024 7:27 am, legg wrote:
On Sat, 8 Jun 2024 03:29:11 +1000, Bill Sloman <bill.sloman@ieee.org><snip>
wrote:
On 7/06/2024 11:24 pm, legg wrote:
On Fri, 7 Jun 2024 14:03:16 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 7/06/2024 4:05 am, legg wrote:
On Thu, 6 Jun 2024 23:18:12 +1000, Bill Sloman <bill.sloman@ieee.org> >>>>>> wrote:
On 6/06/2024 1:46 pm, legg wrote
Right, I see Q2 normally inverted.
C2 seems unneccessarily loaded.
If you are talking about the .asc file I posted on the 3rd June, Q2
isn't "normally inverted" - its mostly on, and it gets turned off for
the 30nsec in which the stretched pulse is being generated. Inverted >operation of a bipolar transistor is usually taken to mean running
current through them in the opposite direction than is seen in normal >operation.
C2 isn't carrying any current worth worrying about. It stabilises the
voltage at the base of Q3 against the base current drawn when the output >pulse is turned on and turned off, -6.7mA when it is turned on an +2mA
when it is turned off, and holds the voltage excursion down to 3.7mV,
not that I ever bothered working this out.
If you want to discuss when the circuit does and how it does it, feel
free, but this wasn't a good start.
--
Bill Sloman, Sydney
On Wed, 12 Jun 2024 00:35:59 +1000, Bill Sloman <bill.sloman@ieee.org wrote:<snip>
On 11/06/2024 7:27 am, legg wrote:
On Sat, 8 Jun 2024 03:29:11 +1000, Bill Sloman <bill.sloman@ieee.org wrote: >>>> On 7/06/2024 11:24 pm, legg wrote:
On Fri, 7 Jun 2024 14:03:16 +1000, Bill Sloman <bill.sloman@ieee.org> wrote:
On 7/06/2024 4:05 am, legg wrote:
On Thu, 6 Jun 2024 23:18:12 +1000, Bill Sloman <bill.sloman@ieee.org> wrote:
On 6/06/2024 1:46 pm, legg wrote
Right, I see Q2 normally inverted.
C2 seems unneccessarily loaded.
If you are talking about the .asc file I posted on the 3rd June, Q2
isn't "normally inverted" - its mostly on, and it gets turned off for
the 30nsec in which the stretched pulse is being generated. Inverted
operation of a bipolar transistor is usually taken to mean running
current through them in the opposite direction than is seen in normal
operation.
Just returning to this, trying to see what determines the switch from non-switching to astable operation (ECLTN0E - ECLTN0D). Misreading a
current and voltage waveform with similar color coding.
C2 isn't carrying any current worth worrying about. It stabilises the
voltage at the base of Q3 against the base current drawn when the output
pulse is turned on and turned off, -6.7mA when it is turned on an +2mA
when it is turned off, and holds the voltage excursion down to 3.7mV,
not that I ever bothered working this out.
If you want to discuss when the circuit does and how it does it, feel
free, but this wasn't a good start.
Not so much interested in the circuit, as its reaction to model
parameters presented by similar devices.
Not Beta, Tr or Tf in this case.
On Fri, 08 Mar 2013 01:18:53 -0600,John_Fiel<jfie...@austininstruments.com>
On 12/06/2024 1:27 am, legg wrote:
On Wed, 12 Jun 2024 00:35:59 +1000, Bill Sloman <bill.sloman@ieee.org wrote: >>> On 11/06/2024 7:27 am, legg wrote:<snip>
On Sat, 8 Jun 2024 03:29:11 +1000, Bill Sloman <bill.sloman@ieee.org wrote:
On 7/06/2024 11:24 pm, legg wrote:
On Fri, 7 Jun 2024 14:03:16 +1000, Bill Sloman <bill.sloman@ieee.org> wrote:
On 7/06/2024 4:05 am, legg wrote:
On Thu, 6 Jun 2024 23:18:12 +1000, Bill Sloman <bill.sloman@ieee.org> wrote:
On 6/06/2024 1:46 pm, legg wrote
Right, I see Q2 normally inverted.
C2 seems unneccessarily loaded.
If you are talking about the .asc file I posted on the 3rd June, Q2
isn't "normally inverted" - its mostly on, and it gets turned off for
the 30nsec in which the stretched pulse is being generated. Inverted
operation of a bipolar transistor is usually taken to mean running
current through them in the opposite direction than is seen in normal
operation.
Just returning to this, trying to see what determines the switch from
non-switching to astable operation (ECLTN0E - ECLTN0D). Misreading a
current and voltage waveform with similar color coding.
C2 isn't carrying any current worth worrying about. It stabilises the
voltage at the base of Q3 against the base current drawn when the output >>> pulse is turned on and turned off, -6.7mA when it is turned on an +2mA
when it is turned off, and holds the voltage excursion down to 3.7mV,
not that I ever bothered working this out.
If you want to discuss when the circuit does and how it does it, feel
free, but this wasn't a good start.
Not so much interested in the circuit, as its reaction to model
parameters presented by similar devices.
You need to work out how the emitter-couple monostable works.
https://www.daenotes.com/electronics/digital-electronics/monostable-multivibrators-working-construction-types
actually does try to spell this out (in it's second section on >emitter-coupled monstables) . It doesn't do it well, but it does it well >enough that you should be able to work out what is going on, and keep
track of the base-emitter voltages across both transistors and their
effect on the collector current.
The Gummel-Poon transistor model keeeps track of the various currents
flowing in and out of each transistor junction while this is going on,
and subtle differences in the parameter values can give you different >currents (and different trajectories)
Not Beta, Tr or Tf in this case.
If you don't know what the circuit is doing, speculation about what the
model might be doing it is a bit pointless.
The emitter-coupled monstable isn't well understood here.
This is from the end of a long thread in 2013.
On Mar 9,
3:54=A0am,JohnLarki<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Fri, 08 Mar 2013 01:18:53 -0600,John_Fiel<jfie...@austininstruments.com>
> wrote:
>
> >On Thu, 07 Mar 2013 16:02:49 -0800, John Larkin
> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>
> >>http://www.highlandtechnology.com/DSS/T240DS.shtml
>
> >---
> >That's not a pulse stretcher, cheater, that's a puls_generator_.
>
> It's a one-shot. It has no internal trigger. It generates no pulses.
>
> And neither you nor Jim have a clue as to how this might be done.
>
> We have a customer who wants us to take this down to 10 ps
pulses. At that point, I'm not sure that I know how that might be done.
We're thinking about it.
http://books.google.co.nz/books?id=3D-pi4vP6xMOQC&pg=3DPA571&lpg=3DPA571&dq= >=3D%22emitter-coupled%22+monostable&source=3Dbl&ots=3DCFsGlVE2YN&sig=3DTUbj= >QhyQPk_cd5tj_UKlIhFVXt8&hl=3Den&sa=3DX&ei=3DTZw6UYmmPMeNyAHA4oHYAg&ved=3D0C= >EIQ6AEwAw#v=3Donepage&q=3D%22emitter-coupled%22%20monostable&f=3Dfalse
describes the emitter-coupled monostable. Put one together out of a
pair of wide-band transistors - BFR92 or better - with 33R up against
each base, and you can certainly get below 10nsec. Since the mechanism >depends on the change of base-emitter impedance with emitter current,
it isn't as easy as it might be to get a wide range of output pulse
widths.
Jim Thompson could probably remember a better solution for you. The >long-obsolete MC10198 ECL monostable
http://www.digchip.com/datasheets/parts/datasheet/343/MC10198-pdf.php
could just get down to 10nsec, but we used two of them when we wanted
to offer long pulses as well - being able to switch in bigger
capacitors put too much stray capacitance on the relevant input pin
for 10nsec operation.
Something boringly obvious with a constant current ramp and a fast
comparator would do the job, but - as with the MC10198, being able to
switch in bigger capacitors to generate much longer pulses is probably >incompatible with a 10nsec pulse width.
--
Bill Sloman, Sydney
On Wed, 12 Jun 2024 16:30:02 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
On 12/06/2024 1:27 am, legg wrote:
On Wed, 12 Jun 2024 00:35:59 +1000, Bill Sloman <bill.sloman@ieee.org wrote:<snip>
On 11/06/2024 7:27 am, legg wrote:
On Sat, 8 Jun 2024 03:29:11 +1000, Bill Sloman <bill.sloman@ieee.org wrote:
On 7/06/2024 11:24 pm, legg wrote:
On Fri, 7 Jun 2024 14:03:16 +1000, Bill Sloman <bill.sloman@ieee.org> wrote:
On 7/06/2024 4:05 am, legg wrote:
On Thu, 6 Jun 2024 23:18:12 +1000, Bill Sloman <bill.sloman@ieee.org> wrote:
On 6/06/2024 1:46 pm, legg wrote
The only parameters that I see in the ECLTN0E model that differs from
it's 'grouping', is a half order magnitude reduction in all junction capacitances - this feature acting to prevent oscillatory behavior, monostable or otherwise. It's ECL companion models oscillate (astable) generally, despite Rbb parameters ranging over two orders of
magnitude, in this circuit configuration.
Sysop: | Keyop |
---|---|
Location: | Huddersfield, West Yorkshire, UK |
Users: | 415 |
Nodes: | 16 (2 / 14) |
Uptime: | 159:57:08 |
Calls: | 8,707 |
Calls today: | 1 |
Files: | 13,270 |
Messages: | 5,951,386 |