Re: Noise details of AD8237 is not mentioned on datasheet

Dear Sir,

Thanks for your reply. Right now I am working on the design of the current source which is in the picoamp range.  For that I used a AD8237 and LMP7721 with a hermetically sealed  10G resistor. The basic Idea behind this circuit is of Howland Current Pump. The schematic is attached is for your reference. Now I have some question with this circuit.

1) How to measure the output impedance of this circuit and which circuit parameters I will have to consider for theoretical analysis of this circuit ?

2)As this circuit is used for the current sourcing, I am confused weather to calculate total voltage noise or current noise?

Please help me with these issues or suggest a suitable literature for analysis of these parameters If possible.

Thanks

Sameer Ramteke