Other Parts Discussed in Thread: TINA-TI
The OPA847 datasheet gives recommendations for driving capacitive loads by adding an isolation resistor on the output pin of the opamp:
The criterion for setting the RS resistor is a maximum bandwidth, flat frequency response at the load. For the OPA847 operating in a gain of +20, the frequency response at the output pin is very flat to begin with, allowing relatively small values of RS to be used for low capacitive loads. As the signal gain is increased, the unloaded phase margin also increases. Driving capacitive loads at higher gains requires lower RS values than those shown for a gain of +20.
There is also a chart of the recommended value for a gain 20 V/V. However, trying the recommended values in a transimpedance configuration, I need substantially more resistance (roughly a factor of 4) to stabilize the circuit. How are the values of RS calculated for each gain and how do I generalize them to other types of amplifiers such as TIAs?
