I intend to use OPA333 in a precision level shifting application, to receive a negative current input and provide a ground-referenced positive voltage output. I.e., noninverting input is tied to ground, input current from the negative current source goes to the inverting input terminal, with just a feedback resistor (82.5k) from the output terminal to the inverting input terminal. The input signal range is 0 to -24.8 uA, and basically DC (a few Hz bandwidth will suffice).
This is with a single +5.0V supply.
It would be best if this circuit worked as close to zero output as possible.
I do not have a local low negative supply voltage available to use for an auxiliary pulldown on the output, as in fig. 19 of the datasheet.
I can tolerate a few mA wasted load current so I could have for instance a 1 or 2 kOhm pulldown resistor from the output to ground. Would it help much?
Alternatively I could run the output through a diode or npn transistor to get some level shifting action there. I suppose that can work (in conjunction with a 1 or 2 kOhm pulldown to ground probably).
I would appreciate advice on this problem, and I would greatly appreciate some measured value such as OPA333 minimum output voltage with a 1 kOhm load to ground. It seems the datasheet only gives information (even typical) only for load connected to mid-supply. I am not sure that I should trust the SPICE model for this.
[And BTW I find it has apparently some convergence issue incompatibility with LTSpice. Unfortunately I do not have PSpice at the moment. I understand there will not be official support for using the model in your competitor's SPICE program. However, I did try TINA and I find it to be rather awkward at best. I did not manage to do anything useful with it yet, sorry.]
Anyway I suspect this question is best answered from real world prototyping and measurement, that is what I intend but it will be good to have your advice and preferably a measurement in advance. Thank you,
Gerard