A novel heat sink design for low speed flows-a BGA example

The ongoing trend in designing electronic systems is to incorporate increased functionality into ever smaller form factors. In addition, the power dissipation from most IC devices continues to increase. Additional design constraints, such as reducing system acoustic noise and weight, are also becoming more prevalent. The combined effect of all these trends is to create increasingly challenging thermal management situations that demand more efficient heat sinks and optimized designs. In this paper a new class of heat sinks are presented and their performance is compared to Airflow conventional heat sinks. MaxiFlow/sup TM/ heat sinks feature very thin, high ratio fins that radiate at various angles from the base. The result is a very low resistance to airflow and very high efficiency of heat dissipation, especially at low airspeeds. They are also very light in weight, allowing for simple attachment methods and weight savings. To aid in designing thermal solutions that utilize these heat sinks, an analytical model has been developed to predict the thermal resistance as a function of airflow velocity for unducted flow for a conventional design. The improvements of the new design compared to the conventional design will be discussed.