When using an AD8629 in a circuit (see attachment) for in loop capacitive load compensation, the devices shows a very slow response to get within a few uV of the final value. On the order of seconds.
The values for the circuit would be:
CL = 0.4uF
Rf=Rg=4k
Rx=200
Rl ~ 10k
Cf = 1200pF
Vin @ Rg is the output of a DAC typically between 0 and 400mV
Vin @ IN+ is a 200mV dc level.
Power supplies are +/- 2.5 volts.
I've run a quick simulation at my end, and I'm getting the proper response within a few milliseconds, which is on the order of what I would expect. I also realize that the 1200pF is probably too small for the proper compensation.
Is there anything else going on inside these auto zero amplifiers that would present difficulties in a circuit such as this?
Thanks,
Tim
