11 Layout

11.1 Layout Guidelines

Attention to good layout practices is always recommended.

• 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 as possible to the device power supply and ground pins.

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.

11.2 Layout Example

OUT

GND

IN +

Vs

IN -

Via to GND Plane

Supply

Voltage

Bypass

Cap

Ground Plane

Figure 11-1. INA281A Recommended Layout

OUT

GND

Vs

IN -

IN +

Via to GND Plane

Supply

Voltage

Bypass

Cap

Ground Plane

Figure 11-2. INA281B Recommended Layout

INA281-Q1

SBOSA01 – NOVEMBER 2020

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