Comparison of component and system level thermal performance for various thermally enhanced packages and PCB layouts

In high performance disc drive applications, high data rate channel chips packaged in standard QFPs can exceed design rules for maximum junction temperature. To meet these design rules and to add a margin for increased reliability, various thermally enhanced packages were characterized at component and system level, with a goal of cost/power optimization, while meeting package reliability requirements. The thermal environment (heat from neighbor chips on PCB, etc.) was held constant while trying different packages and PCB layouts. At system level, case temperature measurements were made in still air and moving air, using an IR thermography camera. In addition, two alternative thermal pad PCB layouts were evaluated at system level. Trade-offs in reliability and thermal performance for different material sets were then analyzed for present and future applications in terms of overall performance, manufacturability (at IC manufacturer and user), and cost. The resulting matrix of options facilitates decision making.