I know this topic has been discussed a lot, but there seems to be varying opinions about the solutions..
The problem is we are trying to make a current source with an op-amp driving a FET as the load. Our goal is to have a fairly high bandwidth for the regulating loop(couple of 100kHz?), but the output of the op-amp is oscillating.
Using a ADA4807 and a ST P36nE06 mosfet. The values for the series(R2) and parallel(R3) resistors were chosen from the op-amps datasheet about driving capacitive load.
There is a 100nF bypass cap very close to the supply pins, and a 2uF cap also.
We have tried a few things which includes:
Upping the series resistor to 50ohm or 100ohm. Did not fix it.
Adding 1nF cap from output to -vin of the op-amp, together with a 10k or 100k resistor (miller integrator). Did not help.
Changing the 10mOhm resistor to 100mOhm. Did not help either.
The prototype is done on verroboard. I don't know if that could be an issue?
I would think this op-amp would be able to drive any capacitive load, but it doesn't seem to work for us. What are we doing wrong?