Is there still an engineering Usenet group where the vast majority of
posts are on topic for electronic design?
In case there are any electronic engineers still watching this group,
here is my question:
I need to design a TIA of bandwidth up to 5 MHz. The analog anti
aliasing filter is to be set at 5 MHz. I would like the front end to
have a transimpedance value of 4.02 kohm. The A to D converter's sample
rate is to be 10 MHz. So that the A to D conversions will alias very
little noise in the bandwidth region 5 MHz, to 10 MHz, I need resistors
that have self resonance well beyond 10 MHz.
So now I am looking at HF resistors. Because noise is primarily
determined by the gain of the first stage, it is desirable for the front end's feedback resistor to be 4.02 kohm.
The Vishay FC series resistors are made in values only up to 1 kohm.
They are very expensive, and so I am reluctant to put 4 of these 1 kohm resistors in series. They are, however, available.
The Visay HCHP series is made in values well beyond 4.02 kohm. But I
cannot find them on the shelf anywhere, and they are extraordinarily expensive. The minimum buy makes them cost prohibitive to acquire, and
the lead times are too long.
I would appreciate advice on any alternatives.
I am not able to find device models for the common thin film metal resistors. I do not know how well they would work up to 10 MHz. I would
like to hear from any who are experienced in using them up this frequency.
Is there still an engineering Usenet group where the vast majority of
posts are on topic for electronic design?
In case there are any electronic engineers still watching this group,
here is my question:
I need to design a TIA of bandwidth up to 5 MHz. The analog anti
aliasing filter is to be set at 5 MHz. I would like the front end to
have a transimpedance value of 4.02 kohm. The A to D converter's sample
rate is to be 10 Mhz. So that the A to D conversions will alias very
little noise in the bandwidth region 5 MHz, to 10 MHz, I need resistors
that have self resonance well beyond 10 MHz.
So now I am looking at HF resistors. Because noise is primarily
determined by the gain of the first stage, it is desirable for the front >end's feedback resistor to be 4.02 kohm.
The Vishay FC series resistors are made in values only up to 1 kohm.
They are very expensive, and so I am reluctant to put 4 of these 1 kohm >resistors in series. They are, however, available.
The Visay HCHP series is made in values well beyond 4.02 kohm. But I
cannot find them on the shelf anywhere, and they are extraordinarily >expensive. The minimum buy makes them cost prohibitive to acquire, and
the lead times are too long.
I would appreciate advice on any alternatives.
I am not able to find device models for the common thin film metal
resistors. I do not know how well they would work up to 10 MHz. I would
like to hear from any who are experienced in using them up this frequency.
Is there still an engineering Usenet group where the vast majority of
posts are on topic for electronic design?
In case there are any electronic engineers still watching this group,
here is my question:
I need to design a TIA of bandwidth up to 5 MHz. The analog anti
aliasing filter is to be set at 5 MHz. I would like the front end to
have a transimpedance value of 4.02 kohm. The A to D converter's sample
rate is to be 10 Mhz. So that the A to D conversions will alias very
little noise in the bandwidth region 5 MHz, to 10 MHz, I need resistors
that have self resonance well beyond 10 MHz.
So now I am looking at HF resistors.
I am not able to find device models for the common thin film metal
resistors. I do not know how well they would work up to 10 MHz. I would
like to hear from any who are experienced in using them up this frequency.
On Tuesday, July 26, 2022 at 9:13:00 AM UTC+10, Artist wrote:
Is there still an engineering Usenet group where the vast majority of
posts are on topic for electronic design?
In case there are any electronic engineers still watching this group,
here is my question:
I need to design a TIA of bandwidth up to 5 MHz. The analog anti
aliasing filter is to be set at 5 MHz. I would like the front end to
have a transimpedance value of 4.02 kohm. The A to D converter's sample
rate is to be 10 MHz. So that the A to D conversions will alias very
little noise in the bandwidth region 5 MHz, to 10 MHz, I need resistors
that have self resonance well beyond 10 MHz.
So now I am looking at HF resistors. Because noise is primarily
determined by the gain of the first stage, it is desirable for the front
end's feedback resistor to be 4.02 kohm.
The Vishay FC series resistors are made in values only up to 1 kohm.
They are very expensive, and so I am reluctant to put 4 of these 1 kohm
resistors in series. They are, however, available.
The Visay HCHP series is made in values well beyond 4.02 kohm. But I
cannot find them on the shelf anywhere, and they are extraordinarily
expensive. The minimum buy makes them cost prohibitive to acquire, and
the lead times are too long.
I would appreciate advice on any alternatives.
Element 14 has Susumu 4.02k 0.1% parts in stock for less than a dollar each1 Megohm resistor into a video preamp and it worked fine.
https://4donline.ihs.com/images/VipMasterIC/IC/SUSU/SUSU-S-A0004582566/SUSU-S-A0004582566-1.pdf?hkey=52A5661711E402568146F3353EA87419
As surface mount parts they will be L-trimmed and have very little inductance or parallel capacitance. They will be fine at 5MHz, as John Larkin has pointed out. Back in the mid-1980's we got shocked when Philips put an L-trimmer surface mount roughly
I am not able to find device models for the common thin film metal
resistors. I do not know how well they would work up to 10 MHz. I would
like to hear from any who are experienced in using them up this frequency.
Philips - once a upon a time - published frequency response data for their spiral trimmed axial metal film resistors. The L-trimmed sufrace mount part did much better than that. Going to Vishay for you job would be an overkill.
Is there still an engineering Usenet group where the vast majority of
posts are on topic for electronic design?
In case there are any electronic engineers still watching this group,
here is my question:
I need to design a TIA of bandwidth up to 5 MHz.
The analog anti aliasing filter is to be set at 5 MHz. I would like
the front end to have a transimpedance value of 4.02 kohm. The A to D converter's sample rate is to be 10 Mhz. So that the A to D
conversions will alias very little noise in the bandwidth region 5
MHz, to 10 MHz, I need resistors that have self resonance well beyond
10 MHz.
So now I am looking at HF resistors. Because noise is primarily
determined by the gain of the first stage, it is desirable for the
front end's feedback resistor to be 4.02 kohm.
The Vishay FC series resistors are made in values only up to 1 kohm.
They are very expensive, and so I am reluctant to put 4 of these 1
kohm resistors in series. They are, however, available.
The Visay HCHP series is made in values well beyond 4.02 kohm. But I
cannot find them on the shelf anywhere, and they are extraordinarily
expensive. The minimum buy makes them cost prohibitive to acquire,
and the lead times are too long.
I would appreciate advice on any alternatives.
I am not able to find device models for the common thin film metal
resistors. I do not know how well they would work up to 10 MHz. I
would like to hear from any who are experienced in using them up this frequency.
BS Artist ? wrote:
==============
Is there still an engineering Usenet group where the vast majority of
posts are on topic for electronic design?
In case there are any electronic engineers still watching this group,
here is my question:
** Thanks for the insults.
I need to design a TIA of bandwidth up to 5 MHz. The analog anti
aliasing filter is to be set at 5 MHz. I would like the front end to
have a transimpedance value of 4.02 kohm. The A to D converter's sample
rate is to be 10 Mhz. So that the A to D conversions will alias very
little noise in the bandwidth region 5 MHz, to 10 MHz, I need resistors
that have self resonance well beyond 10 MHz.
** Where is the problem ?
So now I am looking at HF resistors.
** Why?
I am not able to find device models for the common thin film metal
resistors. I do not know how well they would work up to 10 MHz. I would
like to hear from any who are experienced in using them up this frequency.
** Ever heard of Google ?
https://passive-components.eu/resistor-voltage-and-frequency-dependence/
Note. The letter W has been substituted for the ohm symbol omega in the captions.
..... Phil
Artist wrote:
Is there still an engineering Usenet group where the vast majority of
posts are on topic for electronic design?
I'd recommend Guy Macon's moderated group. misc.business.product-dev,
but it died out 15 or so years back. (Old inhabitants of SED will remember.)
In case there are any electronic engineers still watching this group,
here is my question:
I need to design a TIA of bandwidth up to 5 MHz.
Is it for a photodiode, or something else? The usual issue is input capacitance.
The analog anti aliasing filter is to be set at 5 MHz. I would like
the front end to have a transimpedance value of 4.02 kohm. The A to D
converter's sample rate is to be 10 Mhz. So that the A to D
conversions will alias very little noise in the bandwidth region 5
MHz, to 10 MHz, I need resistors that have self resonance well beyond
10 MHz.
So now I am looking at HF resistors. Because noise is primarily
determined by the gain of the first stage, it is desirable for the
front end's feedback resistor to be 4.02 kohm.
The Vishay FC series resistors are made in values only up to 1 kohm.
They are very expensive, and so I am reluctant to put 4 of these 1
kohm resistors in series. They are, however, available.
The Visay HCHP series is made in values well beyond 4.02 kohm. But I
cannot find them on the shelf anywhere, and they are extraordinarily
expensive. The minimum buy makes them cost prohibitive to acquire,
and the lead times are too long.
I would appreciate advice on any alternatives.
What problem are you trying to solve? As others have mentioned, you can
use a 4k resistor up into the hundreds of megahertz with no issues. You shouldn't even notice its shunt capacitance.
I am not able to find device models for the common thin film metal
resistors. I do not know how well they would work up to 10 MHz. I
would like to hear from any who are experienced in using them up this
frequency.
The main issue is that the shunt capacitance across a resistor depends
on the configuration of nearby conductors and dielectrics.
Last week I was tweaking up a TIA with a 10M feedback resistor that
works up beyond 1 MHz. It uses a combination of a bootstrapped pour on
one end of the resistor and an adjustable RC lead-lag network to flatten
out the gain.
From an RC point of view, that's about 500 times harder than what
you're aiming at--the shunt capacitance of a SMT resistor all by itself
is about 0.1 pF, and it's more like 0.05 pF when mounted on a
ground-plane PC board. (You can measure this yourself, if you pony up
$100 for a used Boonton 72 three-terminal capacitance meter.)
At 4k, the RC corner frequency will be around
f_c ~= 1/(2 pi * 4k * 100 fF) = 400 MHz,
and probably well above that when it's board-mounted. Any bandwidth problems you may be having are coming from elsewhere.
Cheers
Phil Hobbs
BS Artist ? wrote:
==============
Is there still an engineering Usenet group where the vast majority of
posts are on topic for electronic design?
In case there are any electronic engineers still watching this group,
here is my question:
** Thanks for the insults.
BS Artist ? wrote:
==============
Is there still an engineering Usenet group where the vast majority of
posts are on topic for electronic design?
In case there are any electronic engineers still watching this group,
here is my question:
** Thanks for the insults.
He insulted engineers, not you.
jla...@highlandsniptechnology.com wrote:
================================
BS Artist ? wrote:
==============
Is there still an engineering Usenet group where the vast majority of
posts are on topic for electronic design?
In case there are any electronic engineers still watching this group,
here is my question:
** Thanks for the insults.
He insulted engineers, not you.
** The "BS Artist" troll insulted the entire NG, including YOU.
JL treats usenet posting as a joke, a self fulfilling belief in his case.
..... Phil
jla...@highlandsniptechnology.com wrote:
================================
BS Artist ? wrote:
==============
Is there still an engineering Usenet group where the vast majority of
posts are on topic for electronic design?
In case there are any electronic engineers still watching this group,
here is my question:
** Thanks for the insults.
He insulted engineers, not you.
** The "BS Artist" troll insulted the entire NG, including YOU.
JL treats usenet posting as a joke, a self fulfilling belief in his case.
..... Phil
On 7/26/22 05:34, Phil Hobbs wrote:<snip>
Artist wrote:
Is there still an engineering Usenet group where the vast majority of
posts are on topic for electronic design?
I'd recommend Guy Macon's moderated group. misc.business.product-dev,
but it died out 15 or so years back. (Old inhabitants of SED will
remember.)
In case there are any electronic engineers still watching this group,
here is my question:
I need to design a TIA of bandwidth up to 5 MHz.
Is it for a photodiode, or something else? The usual issue is input
capacitance.
It will be a photodiode, currently it is the OSI Optoelectronics InGaAs-120L-FC . This might change. https://www.osioptoelectronics.com/standard-products/ingaas-photodiodes/high-speed-ingaas.aspx
The currently selected op amp is the LTC6226 https://www.analog.com/en/products/ltc6226.html#product-overview
or the TMUX7462F
https://www.ti.com/lit/ds/symlink/tmux7412f.pdf
I would like to be able to have several gain options for the first stage
gain from 4K all the way up to 630k. The switch in consideration for
this is:
MAX14777.
https://datasheets.maximintegrated.com/en/ds/MAX14777.pdf
TMUX7412F
https://www.ti.com/product/TMUX7412F
The current idea is to have a high value resistor in the vicinity of
630k in parallel with the switches, and arrange the switches to switch a choice of one of 4 parallel resistors. The would provide 5 gain options.
and more if more then one resistor is switched into the feedback path. I
know having this option will add capacitance to the virtual ground, even though the analog switch would be between the op amp output, and the resistors.
I am aware of your virtual ground bootstrap techniques for high
capacitance photodiodes to raise bandwidth, and reduce noise, by
reducing the capacitance seen by the virtual ground. I do not know right
now if bootstraping would add more capacitance than would be reduced.
Is the next edition of your book in which you describe bootstrapping out?
I already have the one before it.
On a sunny day (Wed, 27 Jul 2022 02:39:02 -0700 (PDT)) it happened Phil >Allison <pallison49@gmail.com> wrote in ><ba1abfe4-a39e-4fe4-9864-06fe4f4bf79cn@googlegroups.com>:
jla...@highlandsniptechnology.com wrote:
================================
BS Artist ? wrote:
==============
Is there still an engineering Usenet group where the vast majority of >>> >> posts are on topic for electronic design?
In case there are any electronic engineers still watching this group, >>> >> here is my question:
** Thanks for the insults.
He insulted engineers, not you.
** The "BS Artist" troll insulted the entire NG, including YOU.
JL treats usenet posting as a joke, a self fulfilling belief in his case. >>
..... Phil
Jo La is just an ego tripper
his business must run bad with all that time on his hands to post here
and insult people.
BS Artist ? wrote:
==============
Is there still an engineering Usenet group where the vast majority of >>> >> posts are on topic for electronic design?
In case there are any electronic engineers still watching this group, >>> >> here is my question:
** Thanks for the insults.
He insulted engineers, not you.
** The "BS Artist" troll insulted the entire NG, including YOU.
JL treats usenet posting as a joke, a self fulfilling belief in his case. >>
Jo La is just an ego tripper
his business must run bad with all that time on his hands to post here
and insult people.
Actually, biz is excellent and trending better.
John Larkin wrote:
-------------------------------
>
BS Artist ? wrote:
==============
Is there still an engineering Usenet group where the vast majority of >>>>>>> posts are on topic for electronic design?
In case there are any electronic engineers still watching this group, >>>>>>> here is my question:
** Thanks for the insults.
He insulted engineers, not you.
** The "BS Artist" troll insulted the entire NG, including YOU.
JL treats usenet posting as a joke, a self fulfilling belief in his case. >>>>
Jo La is just an ego tripper
his business must run bad with all that time on his hands to post here
and insult people.
Actually, biz is excellent and trending better.
** Despite JL's presence , not because of it.
Seem many examples of exactly that, where staff have to conspire to keep their nutty boss at bay.
..... Phil
John Larkin wrote:
-------------------------------
BS Artist ? wrote:
==============
Is there still an engineering Usenet group where the vast majority of >> >>> >> posts are on topic for electronic design?
In case there are any electronic engineers still watching this group, >> >>> >> here is my question:
** Thanks for the insults.
He insulted engineers, not you.
** The "BS Artist" troll insulted the entire NG, including YOU.
JL treats usenet posting as a joke, a self fulfilling belief in his case. >> >>
Jo La is just an ego tripper
his business must run bad with all that time on his hands to post here
and insult people.
Actually, biz is excellent and trending better.
** Despite JL's presence , not because of it.
On Wed, 27 Jul 2022 16:30:12 -0700 (PDT), Phil Allison
<palli...@gmail.com> wrote:
John Larkin wrote:
BS Artist ? wrote:
JL treats usenet posting as a joke, a self fulfilling belief in his case.
Jo La is just an ego tripper. His business must run bad with all that time on his hands to post here and insult people.
Actually, biz is excellent and trending better.
** Despite JL's presence , not because of it.
No, really, I have function. Crazy ideas. Inventing things.
Nowadays, I can't do everything. FPGAs, Linux, Python test set software, PCB layout, mechanical design, all that can be mostly delegated to saner people.
"Oh, but it just may be a lunatic you're looking for..."
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