8 Detailed Description

8.1 Overview

The INA241x is a high-side, inline, or low-side bidirectional, high-speed current-sense amplifier that offers a

wide common-mode range, precision, zero-drift topology, excellent common-mode rejection ratio (CMRR), and

features enhanced pulse width modulation (PWM) rejection at the inputs of the device. Enhanced PWM rejection

reduces the effect of common-mode transients that can propagate to the output signal that are associated with

PWM input signals. Multiple gain versions are available to allow for the optimization of the desired full-scale

output voltage based on the target current range expected in the application.

8.2 Functional Block Diagram

+

–

REF2

REF1

VS

GND

OUT

IN+

IN–

PWM

Rejection

8.3 Feature Description

8.3.1 Amplifier Input Common-Mode Signal

The INA241x supports large input common-mode voltages from –5 V to +110 V. The internal topology of the

INA241x allows the common-mode range to exceed the power-supply voltage (VS). This allows for the INA241x

to be used for low-side, inline, and high-side current-sensing applications that extend beyond the supply range of

2.7 V to 20 V.

8.3.1.1 Enhanced PWM Rejection Operation

The enhanced PWM rejection feature of the INA241x provides increased attenuation of large common-mode

ΔV/Δt transients. Large ΔV/Δt common-mode transients associated with PWM signals are employed in

applications such as motor or solenoid drive and switching power supplies. The disturbances that can occur

at the output of a current sense amplifier from common-mode transients causes erroneous measurements

and impose limitations when the output is valid. The INA241x is designed with high common-mode rejection

techniques to reduce large ΔV/Δt transients before the system is disturbed. As a result, this makes system

design simple with INA241x. The high AC CMRR, in conjunction with signal bandwidth, allows the INA241x to

minimize output disturbances and ringing during common-mode transitions when compared against traditional

current-sensing amplifiers.

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INA241A, INA241B

SBOSA30A – MARCH 2022 – REVISED AUGUST 2022

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