9 Power Supply Recommendations

The input circuitry of the INAx290 can accurately measure beyond the power-supply voltage. The power supply

can be 20 V, whereas the load power-supply voltage at IN+ and IN– can go up to 120 V. The output voltage

range of the OUT pin is limited by the voltage on the VS pin and the device swing to the supply specification.

10 Layout

10.1 Layout Guidelines

TI always recommends to follow good layout practices:

• Connect the input pins to the sensing resistor using a Kelvin or 4-wire connection. This connection technique

makes sure that only the current-sensing resistor impedance is detected between the input pins. Poor routing

of the current-sensing resistor commonly results in additional resistance present between the input pins.

Given the very low ohmic value of the current resistor, any additional high-current carrying impedance can

cause significant measurement errors.

• Place the power-supply bypass capacitor as close to the device power supply and ground pins as possible.

The recommended value of this bypass capacitor is 0.1 µF. Additional decoupling capacitance can be added

to compensate for noisy or high-impedance power supplies.

• When routing the connections from the current-sense resistor to the device, keep the trace lengths as short

as possible.

10.2 Layout Examples

4

2

IN±

OUT

Current Sense

Output

GND

Load

VIA to Ground

Plane

(2.7 V to 20 V)

5

1

IN+

VS 3

Direction of

Current Flow

Bus Voltage

TI Device

Figure 10-1. Recommended Layout for the INA290

www.ti.com

INA290, INA2290, INA4290

SBOS961C – JUNE 2020 – REVISED JUNE 2021

Copyright © 2021 Texas Instruments Incorporated

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