Abstract:

Computational fluid dynamics (CFD) simulations are performed for a Plastic Quad Flat Package (PQFP) in the JEDEC recommended enclosure for thermal measurements in a natural convection environment to assess the impact of compact thermal modeling strategies on solution run time. The effect of package die and pad size, relative to the package dimensions are also examined to determine their effect on the adequacy of the predicted thermal behavior from these compact thermal models. Simulation results using a simple block on lead model and a thermal resistance model are compared to those from a detailed model of the package. The results show that die size has a predominate effect on temperature predictions form compact models. For large die size, where heat transfer is more one-dimensional in nature, these compact models adequately predict the thermal behavior of the electronic package.