TPS73801: temperature caculate

Hi Jeff,

This is correct, this is a rough estimation of the temperature increase that you would see from ambient temperature that the die would reach. 4.2W of power is quite high for an LDO to process as you have to remember this is a dissipative device, not a high efficiency switcher, that power is being burned and turned into heat energy through resistive processes.

The datasheet goes over these calculations as you have in your question in section 10.3.1

Under these conditions the device would cycle through thermal shutdown never having a stable DC output.

However, by thermally optimizing the board, app note linked here, you can see significant increases in thermal performance from an LDO. Roughly decreasing the operating temperature increase to ~127C compared to 212.1C.

Regards,

John