An experimental assessment of compact thermal models for the prediction of board-mounted electronic component heat transfer

The predictive performance of component compact thermal models (CTMs) implemented in a computational fluid dynamics (CFD) code is assessed for the analysis of board-mounted electronic component heat transfer. This is achieved by comparing numerical predictions with experimental measurements of component junction temperature and component-PCB surface temperature, measured using thermal test chips and infrared thermography respectively. The test vehicles consist of two different package types (SO8 and PQFP208), individually mounted on different printed circuit board (PCB) constructions, which were thermally characterized in a range of convective environments. Component and board detailed modeling are based on nominal dimensions and material properties. A systematic approach is employed to permit potential sources of predictive discrepancies to be isolated. Using a detailed component modeling approach, component junction temperature predictive accuracy was overall within ±3°C or 5% of measurement, demonstrating the robustness of the detailed component and board modeling methodologies. Using star-shaped and shunted resistor network-based CTMs, predictive accuracy was found to decay by 7% to 20% relative to the detailed component models. The coupling of the CTM to the board was shown to impact on predictive accuracy, and suggestions were made to improve CTM implementation in the CFD code.