(1) For more information about traditional and new thermal metrics, see the application report IC Package Thermal Metrics (SPRA953).
(2) The value of RθJA for the PFM (TJ) package of 22°C/W is valid if package is mounted to 1 square inch of copper. The RθJA value can range from 20 to 30°C/W depending on the amount of PCB copper dedicated to heat transfer. See application note AN-1797 TO-263 THIN Package (SNVA328) for more information.