SLVSC31D December 2013 – August 2015 TPS7A4501-SP
The power-handling capability of the device is limited by the maximum-rated junction temperature (125°C). The power dissipated by the device is made up of two components:
Find the GND pin current by using the GND pin current graphs in Typical Characteristics. Power dissipation is equal to the sum of the two components listed previously.
The TPS7A4501-SP regulators have internal thermal limiting designed to protect the device during overload conditions. For continuous normal conditions, do not exceed the maximum junction temperature rating of 125°C. It is important to give careful consideration to all sources of thermal resistance from junction to ambient. Also consider additional heat sources mounted nearby.
For surface-mount devices, heat sinking is accomplished by using the heat-spreading capabilities of the PCB and its copper traces. Copper board stiffeners and plated through-holes can also be used to spread the heat generated by power devices.
Example: Given an output voltage of 3.3 V, an input voltage range of 4 to 6 V, an output current range of 0 to 500 mA, and a maximum case temperature of 50°C, what is the maximum junction temperature?
The power dissipated by the device is equal to:
Using a U package, the thermal resistance is about 10.3°C/W. So the junction temperature rise above case is approximately equal to:
The maximum junction temperature is then equal to the maximum junction-temperature rise above case plus the maximum case temperature or: