Product details

Number of channels 2 Total supply voltage (+5 V = 5, ±5 V = 10) (max) (V) 40 Total supply voltage (+5 V = 5, ±5 V = 10) (min) (V) 2.7 Rail-to-rail In, Out GBW (typ) (MHz) 4.5 Slew rate (typ) (V/µs) 21 Vos (offset voltage at 25°C) (max) (mV) 0.75 Iq per channel (typ) (mA) 0.56 Vn at 1 kHz (typ) (nV√Hz) 10.8 Rating Catalog Operating temperature range (°C) -40 to 125 Offset drift (typ) (µV/°C) 0.3 Features EMI Hardened, High Cload Drive, MUX Friendly, Shutdown, Small Size CMRR (typ) (dB) 130 Iout (typ) (A) 0.075 Architecture CMOS Input common mode headroom (to negative supply) (typ) (V) -0.1 Input common mode headroom (to positive supply) (typ) (V) 0.1 Output swing headroom (to negative supply) (typ) (V) 0.025 Output swing headroom (to positive supply) (typ) (V) -0.025
Number of channels 2 Total supply voltage (+5 V = 5, ±5 V = 10) (max) (V) 40 Total supply voltage (+5 V = 5, ±5 V = 10) (min) (V) 2.7 Rail-to-rail In, Out GBW (typ) (MHz) 4.5 Slew rate (typ) (V/µs) 21 Vos (offset voltage at 25°C) (max) (mV) 0.75 Iq per channel (typ) (mA) 0.56 Vn at 1 kHz (typ) (nV√Hz) 10.8 Rating Catalog Operating temperature range (°C) -40 to 125 Offset drift (typ) (µV/°C) 0.3 Features EMI Hardened, High Cload Drive, MUX Friendly, Shutdown, Small Size CMRR (typ) (dB) 130 Iout (typ) (A) 0.075 Architecture CMOS Input common mode headroom (to negative supply) (typ) (V) -0.1 Input common mode headroom (to positive supply) (typ) (V) 0.1 Output swing headroom (to negative supply) (typ) (V) 0.025 Output swing headroom (to positive supply) (typ) (V) -0.025
SOIC (D) 8 29.4 mm² 4.9 x 6 SOT-23-THN (DDF) 8 8.12 mm² 2.9 x 2.8 TSSOP (PW) 8 19.2 mm² 3 x 6.4 VSSOP (DGK) 8 14.7 mm² 3 x 4.9 WSON (DSG) 8 4 mm² 2 x 2 X2QFN (RUG) 10 3 mm² 1.5 x 2
  • 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
  • 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

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 common-mode 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, high-performance operational amplifier for high-voltage industrial applications.

The OPAx991 family of op amps is available in micro-size 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.

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 common-mode 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, high-performance operational amplifier for high-voltage industrial applications.

The OPAx991 family of op amps is available in micro-size 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.

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Technical documentation

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Type Title Date
* Data sheet OPAx991 40-V Rail-to-Rail Input/Output, Low Offset Voltage, Low Noise Op Amp datasheet (Rev. F) PDF | HTML 04 Jan 2022
Application note Ramping Up on Slew Rate PDF | HTML 13 Jul 2023
Application note DC Parameters: Input Offset Voltage (VOS) (Rev. B) PDF | HTML 31 Mar 2023
Application note Using An Op Amp for High-Side Current Sensing (Rev. A) PDF | HTML 07 Dec 2021
Analog Design Journal Optimizing input and output transient settling times in amplifier circuits PDF | HTML 18 Nov 2021
Circuit design Voltage-to-current (V-I) converter circuit with a Darlington transistor PDF | HTML 14 May 2021
Circuit design AC-coupled transimpedance amplifier circuit PDF | HTML 13 May 2021
Third party documents Programmable analog output circuit maximizes industrial system flexibility 01 Feb 2021
Technical article What is an op amp? 21 Jan 2020
Analog Design Journal Second-sourcing options for small-package amplifiers 26 Mar 2018
Technical article How to lay out a PCB for high-performance, low-side current-sensing designs 06 Feb 2018
Technical article Low-side current sensing for high-performance cost-sensitive applications 22 Jan 2018
Technical article Voltage and current sensing in HEV/EV applications 22 Nov 2017

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Simulation model

Collection of test circuits in TINA-TI to accompany AN1516 (Rev. A)

SBOMBI0A.ZIP (1293 KB) - TINA-TI Reference Design
Simulation model

OPA2991 PSpice Model (Rev. B)

SBOMB49B.ZIP (21 KB) - PSpice Model
Simulation model

OPA2991 TINA-TI Reference Design

SBOMB47.ZIP (12 KB) - TINA-TI Reference Design
Simulation model

OPA2991 TINA-TI SPICE Model

SBOMB48.ZIP (4 KB) - TINA-TI Spice Model
Calculation tool

ANALOG-ENGINEER-CALC — Analog engineer's calculator

The analog engineer’s calculator is designed to speed up many of the repetitive calculations that analog circuit design engineers use on a regular basis. This PC-based tool provides a graphical interface with a list of various common calculations ranging from setting operational-amplifier (...)
Design tool

CIRCUIT060013 — Inverting amplifier with T-network feedback circuit

This design inverts the input signal, VIN, and applies a signal gain of 1000 V/V or 60 dB. The inverting amplifier with T-feedback network can be used to obtain a high gain without a small value for R4 or very large values for the feedback resistors.
Design tool

CIRCUIT060015 — Adjustable reference voltage circuit

This circuit combines an inverting and non-inverting amplifier to make a reference voltage adjustable from the negative of the input voltage up to the input voltage. Gain can be added to increase the maximum negative reference level.
Design tool

CIRCUIT060041 — AC-coupled transimpedance amplifier circuit

This circuit uses an op amp configured as a transimpedance amplifier to amplify the AC signal of a photodiode (modeled by Ii and C3). The circuit rejects DC signals using a transistor to sink DC current out of the photodiode through the use of an integrator in a servo loop. The bias voltage (...)
User guide: PDF
Design tool

CIRCUIT060047 — High-side V-I with darlington pair circuit

This high-side voltage-to-current (V-I) converter delivers a well-regulated current to a load, R4. The circuit accepts an input voltage from 0 V to 10 V and converts it to an output current from 0 A to 5 A. The current is regulated by feeding the voltage across a low-side, current-sense resistor (...)
Design tool

CIRCUIT060074 — High-side current sensing with comparator circuit

This high-side, current sensing solution uses one comparator with a rail-to-rail input common mode range to create an over-current alert (OC-Alert) signal at the comparator output (COMP OUT) if the load current rises above 1 A. The OC-Alert signal in this implementation is active low. So when the (...)
Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Simulation tool

TINA-TI — SPICE-based analog simulation program

TINA-TI provides all the conventional DC, transient and frequency domain analysis of SPICE and much more. TINA has extensive post-processing capability that allows you to format results the way you want them. Virtual instruments allow you to select input waveforms and probe circuit nodes voltages (...)
User guide: PDF
Package Pins Download
SOIC (D) 8 View options
SOT-23-THN (DDF) 8 View options
TSSOP (PW) 8 View options
VSSOP (DGK) 8 View options
WSON (DSG) 8 View options
X2QFN (RUG) 10 View options

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