Plecto
Full Member level 5
I'm struggling to figure out why the circuit below oscillate at about 2-300khz. Changing the value of C10 seems to have no effect, neither does adding an output gate resistor, or adding a input resistor to the non-inverting input. The amplitude of the oscillations goes down if I add a resistor from the op-amp output to ground, but even with a 500Ohm resistor the oscillations are still clear. It doesn't oscillate as long as the output resistance is high enough (Vs_TEY to GND), but it starts to oscillate when the output resistance gets somewhere below 100Ohms. I've though of increasing the gain by using a PNP instead, but I would rather find a solution that works well with a fet as a bipolar transistor would need a constant base current thus making it potentially unsuitable for battery powered operations.