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I have a device that produces a ±30 nA signal and I'd like to measure this to a 0.1 nA precision.

Since the currents are so low and I don't have much time to make mistakes, I am planning to use a TIA embedded in an evaluation board.

Will this do the job?

EVAL-ADA4622-2ARZ

If not, how do I search for something that will work? I don't seem to be finding the things on the datasheets that I was expecting I would.

My plan is to first interface this with an ADC.

JYelton
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JoVi
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  • What bandwidth? What is the current source? Keep in mind you generally want to have the absolute minimum capacitance on the input to a TIA, so cabling must be kept to a minimum. – user1850479 Sep 02 '23 at 18:57
  • JoVi, when you write plus-or-minus, do you really mean that? Do you need two quadrants of operation? – periblepsis Sep 02 '23 at 20:58
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    To use that eval board, you need to change the feedback resistor to create a TIA. Feedback resistor calculation: Rf = Vadc/Imax. If your ADC input voltage range is 3V, then your feedback resistor will be 100M. Getting a circuit to work with resistances in this range is difficult. See my adventures here: https://electronics.stackexchange.com/questions/644934/sensitive-transimpedance-amplifier-oscillates – Mattman944 Sep 02 '23 at 22:12

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