JAJS408M June 2008 – June 2018 TPS735
PRODUCTION DATA.
Thermal protection disables the output when the junction temperature increases to approximately 165°C, which allows the device to cool. When the junction temperature cools to approximately 145°C, the output circuitry is enabled. Depending on power dissipation, thermal resistance, and ambient temperature, the thermal protection circuit cycles on and off. This cycling limits the dissipation of the regulator and protects the regulator from damage as a result of overheating.
Any tendency to activate the thermal protection circuit indicates excessive power dissipation or an inadequate heat sink. For reliable operation, limit junction temperature to 125°C (maximum). To estimate the thermal margin in a complete design (including heat sink), increase the ambient temperature until the thermal protection is triggered. Use worst-case loads and signal conditions. For reliable operation, trigger thermal protection at least 40°C above the maximum expected ambient condition of a 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 TPS735 protects against overload conditions. This protection circuitry is not intended to replace proper heat sinking. Continuously running the TPS735 into thermal shutdown degrades device reliability.