The dynamic characteristics of the OPAx170 have been optimized for common operating conditions. The combination of low closed-loop gain and high capacitive loads decreases the phase margin of the amplifier and can lead to gain peaking or oscillations. As a result, heavier capacitive loads must be isolated from the output. The simplest way to achieve this isolation is to add a small resistor (for example, ROUT equal to 50 Ω) in series with the output. Refer to Figure 39 and Figure 40 illustrate graphs of small-signal overshoot versus capacitive load for several values of ROUT. Also, refer to applications bulletin AB-028, Feedback Plots Define Op Amp AC Performance, for details of analysis techniques and application circuits.
|100-mV Output Step||G = 1|
|100-mV Output Step||G = –1|