OPA187 datasheet(17/54 Pages) TI2

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GM1

+IN

-IN

CHOP1

CHOP2

Notch

Filter

GM_FF

GM2

GM3

OUT

V+

V-

OPA187, OPA2187, OPA4187

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SBOS807E – DECEMBER 2016 – REVISED MAY 2020

Product Folder Links: OPA187 OPA2187 OPA4187

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7 Detailed Description

7.1 Overview

The OPA187, OPA2187, and OPA4187 (OPAx187) operational amplifiers combine precision offset and drift with

excellent overall performance, making these devices an an excellent choice for many precision applications. The

precision offset drift of only 0.001 µV/°C provides stability over the entire temperature range. In addition, these

devices offer excellent overall performance with high CMRR, PSRR, and AOL. As with all amplifiers, applications

with noisy or high-impedance power supplies require decoupling capacitors close to the device pins. In most

cases, 0.1-µF capacitors are adequate.

The OPAx187 is part of a family of zero-drift, low-power, rail-to-rail output operational amplifiers. These devices

operate from 4.5 V to 36 V, are unity-gain stable, and are designed for a wide range of general-purpose

applications. The zero-drift architecture provides ultra-low input offset voltage, and near-zero input offset voltage

drift over temperature and time. This choice of architecture also offers outstanding ac performance, such as ultra-

low broadband noise and zero flicker noise.

7.2 Functional Block Diagram

The functional block diagram shows a representation of the proprietary OPAx187 architecture. Functional blocks

CHOP1 and CHOP2 operate such that the non-idealities of GM1 are cancelled while the input signal is left in-

phase. The integrated notch filter of the OPAx187 family suppresses most of the auto-zero amplifier carrier.

OPA187 Datasheet(PDF) 17 Page - Texas Instruments