Time ( s)

-18

-12

-6

0

6

12

18

24

30

36

42

48

3

2.75

2.5

2.25

2

40

30

20

10

0

Common-Mode Voltage

Output Voltage

Figure 6-4. Enhanced PWM Rejection Performance

6.4 Device Functional Modes

6.4.1 Adjusting the Output With the Reference Pin

The INA790x output is configurable to allow for unidirectional or bidirectional operation. Figure 6-5 shows a

circuit for setting output with an external reference.

PWM

Rejection

Shunt

Resistor

OUT

FB

REF

VS

GND

IS+

IS-

2.7V to 5.5V

+

–

External

Reference

Shunt Current

Alert

LOAD

GND

Rpullup

RFB1

RFB2

+

–

0.1 F

IN-

IN+

Figure 6-5. Adjusting the Output

The output voltage is set by applying a voltage from an external reference at REF. The reference input is

connected to internal gain network. The external resistor network of RFB1 and RFB2, connected to OUT, FB

and REF pins, set up adjustable gain as explained in Adjustable Gain Set Using External Resistors. Output is

set accurately at the voltage provided by external reference as shown in Equation 1 when the resistor RFB2 is

connected to the same voltage as REF pin. The voltage at REF pin can range between supply Vs and GND. For

symmetric bidirectional current sensing REF is set at mid-supply which sets out at mid-supply as well.

VOUT=G× ISHUNT +VREF

(1)

6.4.1.1 Reference Pin Connections for Unidirectional Current Measurements

Unidirectional operation allows current measurements through a resistive shunt in one direction. For

unidirectional operation, connect the device reference pin to the negative rail (see the Ground Referenced

INA790A, INA790B

SBOSAA6B – MAY 2024 – REVISED JULY 2025

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