Thermal modeling of high performance packages in portable computers

Abstract

An experimental and numerical study was conducted to determine the thermal performance of the Pentium(R) Processor in a tape carrier package (TCP) operating inside a typical portable computer. The objective of this study is to develop a validated system level model of the portable environment and demonstrate that equipment designers can carry out design iterations of possible heat transfer configurations to analyze cost, performance, and manufacturability tradeoffs. A detailed three-dimensional (3-D) numerical model of the package was constructed using a computational fluid dynamic software. In the interest of keeping the computational model tractable, some simplifying assumptions were employed to obtain equivalent compact models of the various components in the computer. The fluid motion is essentially a buoyancy driven convection inside an enclosure with multiple discrete heat sources. An experimental study was conducted to validate the numerical model. The results obtained indicate that the model is in good agreement with the experimental data, both qualitatively and quantitatively. Subsequent design iterations were conducted and thermal performance limits were established for various package families. The validated model was used to investigate design modifications to improve thermal performance through increased printed circuit board (PCB) thermal conductivity and the inclusion of heat spreaders, heat pipes, and vented enclosures.