Time (45 ms/div)

C017

V

OUT

V

IN

13

OPA189, OPA2189, OPA4189

www.ti.com

SBOS830 – JUNE 2017

Product Folder Links: OPA189 OPA2189 OPA4189

Submit Documentation Feedback

Copyright © 2017, Texas Instruments Incorporated

8.3 Feature Description

The OPA189, OPA2189, and OPA4189 series of op amps can be used with single or dual supplies from an

common-mode input range does not include midsupply. Supply voltages higher than 40 V can permanently

damage the device; see the Absolute Maximum Ratings table for details. Key parameters are given over the

the supply voltage, temperature range, or frequency are shown in Typical Characteristics.

The OPAx189 is unity-gain stable and free from unexpected output phase reversal. This device uses a

proprietary, periodic autocalibration technique to provide low input offset voltage and very low input offset voltage

drift over time and temperature. For lowest offset voltage and precision performance, optimize circuit layout and

mechanical conditions. Avoid temperature gradients that create thermoelectric (Seebeck) effects in the

thermocouple junctions formed from connecting dissimilar conductors. Cancel these thermally-generated

potentials by ensuring they are equal on both input pins. Other layout and design considerations include:

• Use low thermoelectric-coefficient conditions (avoid dissimilar metals).

• Thermally isolate components from power supplies or other heat sources.

• Shield operational amplifier and input circuitry from air currents, such as cooling fans.

Follow these guidelines to reduce the likelihood of junctions being at different temperatures, which may cause

thermoelectric voltages of 0.1 µV/°C or higher, depending on the materials used. See Layout Guidelines for

details and layout example.

8.3.1 Operating Characteristics

The OPAx189 is specified for operation from 4.5 V to 36 V (±2.25 V to ±18 V). Many specifications apply from

–40°C to +125°C. Parameters that can exhibit significant variance with regard to operating voltage or

temperature are presented in the Typical Characteristics section.

8.3.2 Phase-Reversal Protection

The OPAx189 has an internal phase-reversal protection. Many op amps exhibit a phase reversal when the input

is driven beyond the linear common-mode range. This condition is most often encountered in noninverting

circuits when the input is driven beyond the specified common-mode voltage range, causing the output to

reverse into the opposite rail. The OPAx189 input prevents phase reversal with excessive common-mode

voltage. Instead, the output limits into the appropriate rail. This performance is shown in Figure 4.

Figure 4. No Phase Reversal