This device is specified for current handling of up to 50 A over the entire
–40°C to +85°C temperature range using a 2-oz. copper pour for the input power
plane, as well as no external airflow passing over the device.
The primary current-handling limitation for this device is how much heat is dissipated inside the package. Efforts to improve heat transfer out of the package and into the surrounding environment improve the ability of the device to handle currents of up to 50 A over a wider temperature range.
Heat transfer improvements primarily involve larger copper power traces and
planes with increased copper thickness (2 oz.), as
well as providing airflow to pass over the device.
Thermal vias help spread the current and power
dissipated over multiple board layers. The INA254 evaluation module
(EVM) features a 2-oz. copper pour for the planes,
and is capable of supporting 50 A at temperatures
up to 125°C.
The bypass capacitor should be placed close to device ground and supply pins, but can be moved farther out if needed to avoid cutting thermal planes. 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.