I'd like to try the same unipolar DC current measurement you mentioned that you ran to get measurements of very small currents. That is, I'd like to set up a 4-wire measurement for 0 uA to 1 uA. I'd apply a step voltage of 600 mV and I would set R_TIA to make the max voltage at the output of the TIA be 750 mV (or would it be twice 750 mV for a unipolar setup)?
Is there any app note on this unipolar current measurement aside from the attached two files? I had trouble following the discussion in the .pptx file because on Slide 2 it mentions that the assumption in the ADI example is that they have a 0 uA to 20 uA current into the TIA ... yet all the following slides show 0 uA to 40 uA.
I looked through the code in the SDK 2.3.0 example in the UnipolarCurrentMeasurement workspace, but I think it's set up for a 2-wire measurement? What would I need to change to be able to use it for a 4-wire measurement?
Would I set R_TIA as:
R_TIA = 0.75V/1uA
R_TIA = (2)(0.75V)/1uA