ZHCSHI5D March 2001 – February 2018 TPS791
Specified regulator operation is confirmed at a junction temperature of 125°C; restrict the maximum junction temperature to 125°C under normal operating conditions. This restriction limits the power dissipation the regulator can handle in any given application. To ensure the junction temperature is within acceptable limits, calculate the maximum allowable dissipation, PD(max), and the actual dissipation, PD, which must be less than or equal to PD(max).
The maximum-power-dissipation limit is determined using the following equation:
The regulator dissipation is calculated using:
Power dissipation resulting from quiescent current is negligible. Excessive power dissipation triggers the thermal protection circuit.