OPA992 datasheet(22/50 Pages) TI

22 / 50 page

For additional drive capability in unity-gain configurations, improve capacitive load drive by inserting a small

resistor, RISO, in series with the output, as shown in Figure 7-7. This resistor significantly reduces ringing

and maintains DC performance for purely capacitive loads. However, if a resistive load is in parallel with the

capacitive load, then a voltage divider is created, thus introducing a gain error at the output and slightly reducing

the output swing. The error introduced is proportional to the ratio RISO / RL, and is generally negligible at low

output levels. A high capacitive load drive makes the OPAx992-Q1 an excellent choice for applications such

as reference buffers, MOSFET gate drives, and cable-shield drives. The circuit shown in Figure 7-7 uses an

isolation resistor, RISO, to stabilize the output of an op amp. RISO modifies the open-loop gain of the system for

increased phase margin.

load

out

iso

-V

Figure 7-7. Extending Capacitive Load Drive With the OPA992-Q1

OPA992-Q1, OPA2992-Q1, OPA4992-Q1

SBOSAC9D – AUGUST 2022 – REVISED APRIL 2023

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OPA992 Datasheet(PDF) 22 Page - Texas Instruments