ZHCS516B December 2011 – November 2018 TPS7A4101
PRODUCTION DATA.
Thermal protection disables the output when the junction temperature rises to approximately 170°C, allowing the device to cool. When the junction temperature cools to approximately 150°C, the output circuitry is enabled. Depending on power dissipation, thermal resistance, and ambient temperature, the thermal protection circuit may cycle on and off. This cycling limits the dissipation of the regulator, thus providing protection from damage as a result of overheating.
Any tendency to activate the thermal protection circuit indicates excessive power dissipation or an inadequate heatsink. For reliable operation, junction temperature should be limited to a maximum of 125°C. To estimate the margin of safety in a complete design (including heatsink), increase the ambient temperature until the thermal protection is triggered; use worst-case loads and signal conditions. For good reliability, thermal protection should trigger at least 35°C above the maximum expected ambient condition of the particular application. This configuration produces a worst-case junction temperature of 125°C at the highest expected ambient temperature and worst-case load.
The internal protection circuitry of the TPS7A4101 has been designed to protect against overload conditions. This circuitry is not intended to replace proper heatsinking. Continuously running the TPS7A4101 into thermal shutdown degrades device reliability.