7 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification,

and TI does not warrant its accuracy or completeness. TI’s customers are responsible for

determining suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

7.1 Application Information

7.1.1 Driving a Capacitive Load

The OPAx892 are internally compensated to maximize bandwidth and slew-rate performance. To maintain

stability, take additional precautions when driving capacitive loads with a high-performance amplifier. As a result

of the internal compensation, significant capacitive loading directly on the output node decreases the device

phase margin, and potentially lead to high-frequency ringing or oscillations. Therefore, for capacitive loads

greater than 10 pF, place an isolation resistor in series with the output of the amplifier. Figure 7-1 shows this

configuration. For most applications, a minimum resistance of 20 Ω is recommended. In 75

‑Ω transmission

systems, setting the series resistor value to 75 Ω is a beneficial choice because this value isolates any

capacitance loading and provides source impedance matching.

C

LOAD

V

I

+

–

OPA892

50

20

V

O

1 k

Figure 7-1. Driving a Capacitive Load

7.1.2 General Configuration

When receiving low-level signals, limiting the bandwidth of the incoming signals into the system is often required.

Figure 7-2 shows how the simplest way to accomplish this limiting is to place an RC filter at the noninverting pin

of the amplifier.

+

–

R

F

V

OUT

R

G

R

1

C

1

V

IN

Figure 7-2. Single-Pole Low-Pass Filter

VOUTVIN= 1+RFRG × 11+sR1C1

(1)

OPA892

SLOSEB4 – NOVEMBER 2023

www.ti.com

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