The case is made for the continued use of single valued thermal resistances for the prediction of component junction temperature, and, hence, reliability. These values are adjusted using empirically determined influence factors to account for thermal and aerodynamic interactions at board level. The paper presents measured values of influence factors for arrays of Plastic Quad Flat Packs (PQFPs) over a range of Reynolds numbers and with a series of board level obstacles modeling upstream passive components. The results are formulated into a novel set of design rules.

Issue Section:
Technical Papers
Keywords:
thermal management (packaging), plastic packaging, forced convection, thermal resistance, circuit reliability, Forced Convection Electronic Cooling, Thermal Resistance, Aerodynamic Influence Factors, Plastic Quad Flat Pack (PQFP), Upstream Flow Disturbance, Thermal Design Rules
Topics:
Design, Design methodology, Electronic systems, Flow (Dynamics), Forced convection, Temperature, Thermal resistance, Junctions, Reynolds number, Reliability
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 by ASME
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