6 Detailed Description

6.1 Overview

The INA791x features a precision current sensing design with 400µΩ current-sensing EZShunt™ technology

resistor and supports common-mode voltages up to 110V. The internal amplifier features a precision zero-drift

topology with excellent common-mode rejection ratio (CMRR). High-precision measurements are enabled by

matching the shunt resistor value and the current-sensing amplifier gain across temperature, thus providing

a highly-accurate, system-calibrated method for measuring current. The high-speed current-sensing amplifier

helps output settle fast after the common-mode transients. Flexibility of adjustable gain with two external

resistors allows for the optimization of the desired full-scale output voltage based on the target current range

expected in the application.

6.2 Functional Block Diagram

+

–

Shunt

Resistor

OUT

FB

REF

VS

GND

IS+

IS-

+

–

Alert

IN-

IN+

6.3 Feature Description

6.3.1 Integrated Shunt Resistor

The INA791x features an integrated EZShunt™ technology current-sensing resistor that provides accurate

measurements over the entire specified temperature range of –40°C to +125°C. The integrated current-sensing

resistor provides measurement stability over temperature, and simplifies printed circuit board (PCB) layout and

board constraint difficulties common in high-precision measurements.

The onboard current-sensing resistor is designed as a 4-wire (or Kelvin) connected resistor that enables

accurate measurements through a force-sense connection. Amplifier input pins (IN– and IN+) connected

internally to the sense point of the shunt resistor eliminates many instances of parasitic impedance commonly

found in typical very-low sensing-resistor level measurements. The INA791x is system-calibrated to make sure

that the current-sensing resistor and current-sensing amplifier are both precisely matched to one another. The

in-package integrated sensing resistor must be used with the internal current-sensing amplifier to achieve the

optimized system gain specification.

The INA791x has approximately 550µΩ of package resistance. Of this total package resistance, 400µΩ

resistance from the Kelvin-connected current-sensing resistor is used by the amplifier. The power dissipation

requirements of the system and package are based on the total 550µΩ package resistance between the IS+ and

IS– pins.

www.ti.com

INA791A, INA791B

SBOSAD1A – MAY 2024 – REVISED JULY 2025

Copyright © 2025 Texas Instruments Incorporated

Submit Document Feedback

13

Product Folder Links: INA791A INA791B