I'm trying to use the AD8210 to measure currents in the high-side of a simple BJT regulated power supply.
I saw that after started using the AD8210 for the current control, the output voltage of my power supply didn't go to 0 anymore.
I narrowed the problem to the AD8210 itself, so I got more of those and tried them separatedly
If I only apply 5V to Vs of them, without ANY shunt resistor, nor output load, nor bypass cap, I got around 4.1V in each differential inputs. The same is true if I connect the proper shunt (with no current nor voltage applied to any pin of the shunt).
If I try to ground either input pin with an ammeter, I got almost 5mA that comes from the AD8210 itself.
Why this is happening? I didn't saw anything related to this in the datasheet, and I expected that both differential inputs to behave like a small load (to ground) ONLY when some kind of common-mode voltage was applied externally.
I'm missing something? Should I use another part?