The OPA836 and OPA2836 devices can drive up to a nominal capacitive load of 2.2 pF on the output with no special consideration. When driving capacitive loads greater than 2.2 pF, TI recommends using a small resister (R_O) in series with the output as close to the device as possible. Without R_O, capacitance on the output interacts with the output impedance of the amplifier causing phase shift in the loop gain of the amplifier that will reduce the phase margin. This will cause peaking in the frequency response and overshoot and ringing in the pulse response. Interaction with other parasitic elements may lead to instability or oscillation. Inserting R_O will isolate the phase shift from the feedback path and restore the phase margin; however, R_O can limit the bandwidth slightly.

Figure 8-5 shows the test circuit and Figure 7-43 shows the recommended values of R_O versus capacitive loads, C_L. See Figure 7-40 for the frequency response with various values.

Figure 8-5 R_O versus C_L Test Circuit