APPLICATION OF PHASE-CHANGE MATERIALS FOR PASSIVE THERMAL CONTROL OF PLASTIC QUAD FLAT PACKAGES - A COMPUTATIONAL STUDY

A transient three-dimensional analysis was performed for passive therm al control of a plastic quad flat package by incorporating an organic phase change material (PCM) under the printed wiring board. Governing conservation equations for mass, momentum, and energy were solved by a n implicit finite volume numerical technique. The effects of phase cha nge were modeled by a single-domain enthalpy-porosity technique. To st udy the effects of thermal conductivity of the board, a total of six c ases were considered with two different board materials. It was found that passive cooling with PCM can arrest the temperature rise for subs tantial time, for the power levels considered. A higher board thermal conductivity resulted in a reduction in temperature levels. The melt r egion for a lower thermal conductivity of the board was found to be lo calized near the package footprint, while for a higher board conductiv ity the melt region extends along the board.