+

±

REF2

REF1

VS

GND

OUT

PWM

Rejection

IS+

IS±

IN+

IN±

SH+

SH±

2 m

0.1%

50 k

50 k

+

±

REF2

REF1

VS

GND

OUT

PWM

Rejection

IS+

IS±

IN+

IN±

SH+

SH±

2 m

0.1%

50 k

50 k

REF5025

2.5-V

Reference

17

INA253

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SLOS954A – JULY 2018 – REVISED DECEMBER 2018

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Device Functional Modes (continued)

8.4.4 Reference Pin Connections for Bidirectional Current Measurements

Bidirectional operation allows the INA253 to measure currents through a resistive shunt in two directions. For this

case, set the output voltage anywhere within the reference input limits. A common configuration is to set the

reference inputs at half-scale for equal range in both directions. However, the reference inputs can be set to a

voltage other than half-scale when the bidirectional current is nonsymmetrical.

8.4.4.1 Output Set to External Reference Voltage

Connecting both pins together and then to a reference voltage results in an output voltage equal to the reference

voltage for the condition of shorted input pins or a 0-V differential input. Figure 35 shows this configuration. The

output voltage decreases below the reference voltage when the IN+ pin is negative relative to the IN– pin, and

increases when the IN+ pin is positive relative to the IN– pin. This technique is the most accurate way to bias the

output to a precise voltage.

Figure 35. External Reference Output

8.4.5 Output Set to Mid-Supply Voltage

Figure 36 shows that by connecting one reference pin to VS and the other to the GND pin, the output is set at

half of the supply when there is no differential input. This method creates a ratiometric offset to the supply

voltage, where the output voltage remains at VS / 2 when 0 V is applied between the IN+ and IN– inputs.

Figure 36. Mid-Supply Voltage Output