V+

V–

100kΩ

OPA132 single op amp only.

Use offset adjust pins only to null

offset voltage of op amp—see text.

Trim Range: ±4mV typ

OPA132

6

7

8

4

3

2

1

10nF

10nF

OPA132, OPA2132, OPA4132

www.ti.com

SBOS054B – JANUARY 1995 – REVISED SEPTEMBER 2015

8 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. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The OPAx132 series operational amplifiers are unity-gain stable and suitable for a wide range of general-

purpose applications. Power supply pins should be bypassed with 10-nF ceramic capacitors or larger.

The OPAx132 series operational amplifiers are free from unexpected output phase reversal common with FET

operational amplifiers. Many FET-input operational amplifiers exhibit phase-reversal of the output when the input

common-mode voltage range is exceeded. This can occur in voltage-follower circuits, causing serious problems

in control loop applications. The OPAx132 series of operational amplifiers are free from this undesirable

behavior. All circuitry is completely independent in dual and quad versions, assuring normal behavior when one

amplifier in a package is overdriven or short-circuited.

8.1.1 Operating Voltage

The OPAx132 series of operation amplifiers operate with power supplies from ±2.5 V to ±18 V with excellent

performance. Although specifications are production tested with ±15 V supplies, most behavior remains

unchanged throughout the full operating voltage range. Parameters which vary significantly with operating

voltage are shown in the Typical Characteristics section.

8.1.2 Offset Voltage Trim

Offset voltage of the OPAx132 series of amplifiers is laser trimmed and usually requires no user adjustment. The

OPAx132 amplifier (single op amp version) provides offset voltage trim connections on pins 1 and 8. Offset

voltage can be adjusted by connecting a potentiometer as shown in Figure 18. This adjustment should be used

only to null the offset of the operational amplifier, not to adjust system offset or offset produced by the signal

source. Nulling offset could degrade the offset voltage drift behavior of the operational amplifier. While it is not

possible to predict the exact change in drift, the effect is usually small.

Figure 18. OPAx132 Offset Voltage Trim Circuit

8.1.3 Input Bias Current

The FET-inputs of the OPAx132 series provide very low input bias current and cause negligible errors in most

applications. For applications where low input bias current is crucial, junction temperature rise should be

minimized. The input bias current of FET-input operational amplifiers increases with temperature as shown in

Figure 5.

The OPAx132 series may be operated at reduced power supply voltage to minimize power dissipation and

temperature rise. Using ±3 V supplies reduces power dissipation to one-fifth that at ±15 V.

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Product Folder Links: OPA132 OPA2132 OPA4132