7 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification, and

TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining

suitability of components for their purposes. Customers should validate and test their design

implementation to confirm system functionality.

7.1 Application Information

The INA21x-Q1 family of devices measure the voltage developed across a current-sensing resistor when current

passes through the resistor. The ability to drive the reference pin to adjust the functionality of the output signal

offers multiple configurations, as discussed throughout the Section 7.2 section.

7.2 Typical Applications

7.2.1 Unidirectional Operation

Unidirectional operation allows the INA21x-Q1 family of devices to measure currents through a resistive shunt

in one direction. The most frequent case of unidirectional operation sets the output at ground by connecting the

REF pin to ground. In unidirectional applications where the highest possible accuracy is desirable at very low

inputs, bias the REF pin to a convenient value above 50 mV to get the device output swing into the linear range

for zero inputs.

A less frequent case of unipolar output biasing is to bias the output by connecting the REF pin to the supply. In

this case, the quiescent output for zero input is at quiescent supply. This configuration only responds to negative

currents (inverted voltage polarity at the device input).

CBYPASS

0.1 µF

Power Supply

Load

Output

-

+

IN-

IN+

GND

V+

OUT

REF

Bus Supply

Copyright © 2017, Texas Instruments Incorporated

Figure 7-1. Unidirectional Application Schematic

7.2.1.1 Design Requirements

The device can be configured to monitor current flowing in one direction (unidirectional) or in both directions

(bidirectional) depending on how the REF pin is configured. The most common case is unidirectional where the

output is set to ground when no current is flowing by connecting the REF pin to ground, as shown in Figure 7-1.

When the input signal increases, the output voltage at the OUT pin increases.

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INA210-Q1, INA211-Q1, INA212-Q1, INA213-Q1, INA214-Q1, INA215-Q1

SBOS475K – MARCH 2009 – REVISED NOVEMBER 2023

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Product Folder Links: INA210-Q1 INA211-Q1 INA212-Q1 INA213-Q1 INA214-Q1 INA215-Q1