How thermal analysis tools can be used for testing and evaluating the small outline packages found on reduced-sized PCBs in modern consumer devices.
When IC packages are downsized, thermal power density increases, and the heat-transfer path from the die to the external ambient needs to be optimized to allow for maximum possible power dissipation at the die while still ensuring the die temperature is under the maximum allowable value. Although PSOPs undergo tests for reliability under temperature stresses, electrical flow, and solderability, as well as mechanical inspection at the manufacturer before shipping, it would be time-consuming and expensive to physically test or design test boards to test a package in all its possible applications and configurations.
Source: EEtimes News
Link: Thermal Analysis of PCB Mounted Small Outline Packages