I Would like used AD8422 to measure shunt current as below picture and I have some issue as below:
1. I used 3V and 30k ohm load to simulate 0.1mA current , but I measure 2.5265V from AD8422 Vout.
2. I used 3V and 3k ohm load to simulate 1mA current, but I measure 2.5359V from AD8422 Vout.
3. I used 3V and 300 ohm load to simulate 10mA current , but I measure 2.6290V from AD8422 vout.
This result have some gap with Estimated value((Ishunt x0.1x100)+2.5V) , What's wrong in this schematic? Does AD8422 suitable for shunt current measurement? BTW , If I want to measure uA current , Do you have suggest?
Note: 2.5V REF from ADR3525.