1 Features

• Low offset voltage: ±125 μV

• Low offset voltage drift: ±0.3 μV/°C

• Low noise: 10.8 nV/√Hz at 1 kHz

• High common-mode rejection: 130 dB

• Low bias current: ±10 pA

• Rail-to-rail input and output

• Wide bandwidth: 4.5 MHz GBW

• High slew rate: 21 V/μs

• High capacitive load drive: 1 nF

• MUX-friendly/comparator inputs

– Amplifier operates with differential inputs up to

supply rail

– Amplifier can be used in open-loop or as

comparator

• Low quiescent current: 560 μA per amplifier

• Wide supply: ±1.35 V to ±20 V, 2.7 V to 40 V

• Robust EMIRR performance: EMI/RFI filters on

input and supply pins

• Differential and common-mode input voltage range

to supply rail

2 Applications

• Low-power audio preamplifier

• Multiplexed data-acquisition systems

• Test and measurement equipment

• ADC driver amplifiers

• SAR ADC reference buffers

• Programmable logic controllers

• High-side and low-side current sensing

3 Description

The OPAx991 family (OPA991, OPA2991, and

OPA4991) is a family of high voltage (40 V) general

purpose operational amplifiers. These devices offer

exceptional DC precision and AC performance,

including rail-to-rail input/output, low offset (±125 μV,

typical), low offset drift (±0.3 μV/°C, typical), low noise

(10.5 nV/√Hz and 1.8 μVPP), and 4.5-MHz bandwidth.

Unique features such as differential and commonmode

input-voltage range to the supply rail, high

output current (±75 mA), high slew rate (21 V/μs),

high capacitive load drive (1 nF), and shutdown

functionality make the OPAx991 a robust, highperformance

operational amplifier for high-voltage

industrial applications.

The OPAx991 family of op amps is available in microsize

packages (such as X2QFN and WSON), as well

as standard packages (such as SOT-23, SOIC, and

TSSOP), and is specified from

–40°C to 125°C.