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High frequency photodiode transimpedance amplifier design

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moffy:

--- Quote from: David Hess on June 12, 2020, 09:48:59 pm ---
I have also used a short length of small diameter coaxial cable and trimmed the open end; this has the advantage of being shielded.


--- End quote ---

Cool. :D

arivalagan13:
I'm currently designing a TIA for Faraday cup detectors.
This Texas Instruments presentation was helpful to clear the air with TIA stability problems.
https://training.ti.com/high-speed-transimpedence-amplifier-design-flow

And, Phil Hobbs's book was exceptionally good.

And, Art of Electronics - The X Chapters book has a dedicated section on TIA which kind of consolidates what could be achieved best.

This Texas Instruments presentation might also help, for sure.

David Hess:
Also look for Burr-Brown application notes on the subject.

bobaruni:
I'm not sure if using that particular op amp in that way will give you stability, in the LT1226 datasheet they show a photodiode amplifier on the first page with a gain of 25 where the photodiode is connected to the non inverting input and I assume the main reason is to maintain stability.
The other thing I would mention is that the signal to noise ratio will be low and this may or may not matter depending on your application.

It's been a long time since I have worked on a high speed TIA, I last used a OPA659 and OPA657 with good results and while these op amps will not run on +-15V rails, they don't need to if they are followed by a second gain stage that can run on +-15v rails or better yet an ADC with a matching voltage range to the first op amp.
Note these are both JFET input, I tend to only use FET or CMOS input amplifiers for TIAs as I have had current noise and offset problems with bipolar input op amps in low light situations.

Having said this, the ideal scenario in terms of signal to noise ratio is to have as much gain as possible in the first stage so that the feedback resistor is as high as possible while still permitting the desired bandwidth.

There are some good online calculators for calculating noise such as: http://www.jensign.com/noise/noisecalculator.html
An also bandwidth and stability: http://www.jensign.com/stability/calculator.html
These calculations are key to designing with stability and determining the required feedback capacitor.

Bob.

Marco:
Still don't really see how high speed opamps make much sense ... it will be hard to improve on LTC6560 on any metric.

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