I want to use an OPA 2277 in a voltage follower configuration to drive an analog signal down approximately 2 feet of wire. I plan on using a shielded cable so the capacitance on the op amp output might approach 100-200pf. Can TI advise on what range of output capacitance values can be used with no oscillations?
-Mitch
Hi Mitch,
I simulated a voltage follower configuration up to 1nf and found that the op amp is likely stable, but phase margin is near 50 degree. With 2nf capacitive load, the circuit's phase margin is approx. 47 degree (you need a minimum 45 degree, it is near the edge). It will have some overshoot, but it should not oscillate up to 1nf case.
If you want to compensate the circuit for a large capacitive or complex load, please let us know the required BW. As it is simulated, you have approx. 770kHz at 0dB.
If you have additional questions, please let us know.
Best,
Raymond
