Thermal comparison of plate, extrusion heat sink, and skive heat sink

Abstract

Due to the high power dissipation values of power amplifiers, large temperature gradients exist, resulting in localized hot spots around the devices. These hot spots cause high device junction temperatures. Generally speaking, the higher junction temperature increases, the lower reliability will be. Thus, improving the heat spreading is very important. Several methods can be used to improve heat spreading. Skiving is a process of cutting off in thin layers or paring. Skiving is a high throughput manufacturing process that produces high surface area heat sinks at low cost. The entire extruded material is skived and then the heat sinks are cut to the desired length. The high process throughput results in low cost. In quantities of 1000 units, a 100 mm/spl times/70 mm/spl times/25 mm heat sink costs approximately $3.50. A detailed comparison demonstrates the heat absorption capability of using aluminum plate, aluminum plate with skive heat sink, and extrusion heat sink under laminar flow (free convection) and turbulent flow (forced convection) environments. Two CFD thermal analysis software packages (Icepak and Flotherm) are used to compare experimental results.