The power handling capability of the device is limited by the maximum rated junction temperature (125°C). The power dissipated by the device consists of two components:

• Output current multiplied by the input/output voltage differential: I_OUT × (V_IN – V_OUT)
• GND pin current multiplied by the input voltage: I_GND × V_IN

The GND pin current can be found by examining the GND pin current curves in the Typical Characteristics. Power dissipation is equal to the sum of the two components listed previously.

The TPS798-Q1 series regulators have internal thermal limiting designed to protect the device during overload conditions. Do not exceed the maximum junction temperature rating of 125°C. All sources of thermal resistance from junction to ambient must be carefully considered. Additional heat sources mounted nearby must also be considered.

For surface-mount devices, heat sinking is accomplished by using the heat-spreading capabilities of the printed-circuit-board (PCB) and its copper traces. Copper board stiffeners and plated through-holes can also be used to spread the heat generated by power devices.