Thermal resistance modelling and design optimization of PCB vias

Various reference printed circuit board (PCB) thermal designs have been provided by semiconductor manufacturers and researchers. However, the recommendations are not optimal, and there are some discrepancies among them, which may confuse electrical engineers. This paper aims to develop an analytical thermal model for PCB vias, and further to find the optimal design for thermal resistance minimization. Firstly, the vertical thermal resistance of a PCB via array is analytically modelled. Then the dependence of the thermal resistance on multiple design parameters is analysed, and the optimal via diameter is found for different PCB specifications. Finally, the developed thermal model and optimal trajectory are verified by computational fluid dynamics (CFD) simulations and experiments.