+

±

OPA192

OPA2192

OPA4192

SBOS620A – DECEMBER 2013 – REVISED JANUARY 2014

www.ti.com

For additional drive capability in unity-gain configurations, capacitive load drive can be improved by inserting a

small (10

reduces ringing while maintaining dc performance for purely capacitive loads. However, if there is a resistive load

in parallel with the capacitive load, a voltage divider is created, introducing a gain error at the output and slightly

low output levels. A high capacitive load drive makes the OPA192 well suited for applications such as reference

buffers, MOSFET gate drives, and cable-shield drives. The circuit shown in Figure 52 uses an isolation resistor

margin, and results using the OPA192 are summarized in Table 3. For additional information on techniques to

optimize and design using this circuit, TI Precision Design TIDU032 details complete design goals, simulation,

and test results.

Figure 52. Extending Capacitive Load Drive with the OPA192

Table 3. OPA192 Capacitive Load Drive Solution Using Isolation Resistor Comparison of Calculated and

Measured Results

Capacitive Load

100 pF

1000 pF

0.01 µF

0.1 µF

1 µF

Phase Margin

45°

60°

45°

60°

45°

60°

45°

60°

45°

60°

47.0

360.0

24.0

100.0

20.0

51.0

6.2

15.8

2.0

4.7

Measured

23.2 8.6

10.4

22.5

9.0

22.1

8.7

23.1

8.6

21.0

8.6

Overshoot (%)

Calculated PM

45.1°

58.1°

45.8°

59.7°

46.1°

60.1°

45.2°

60.2°

47.2°

60.2°

For step-by-step design procedure, circuit schematics, bill of materials, PCB files, simulation results, and test

results, refer to TI Precision Design TIDU032 - Capacitive Load Drive Solution using an Isolation Resistor

22

Submit Documentation Feedback

Copyright © 2013–2014, Texas Instruments Incorporated

Product Folder Links: OPA192 OPA2192 OPA4192