Thermal modeling and analysis of a power ball grid array in system-in-package technology

In power electronics, system-in-package (SiP) designs require an approach for the development of an accurate thermal analysis which is different from traditional models. In fact, the power consumption alone of a SiP is not sufficient information for estimating the maximum temperature of the package or the temperature difference of the case when multiple power transistors are working in different configurations. In this paper, we propose a simple methodology to model the thermal behavior of a SiP circuit with eight power transistors and one integrated circuit (IC) driver in a fine pitch plastic ball grid array (BGA) package. The models are described for (i) the heat generation of the active components and (ii) the thermal analysis of the BGA package under test. The validation of the proposed thermal models was carried out through a comparison of the simulation results with experimental data, which were obtained from the thermal analysis by InfraRed thermography. The absolute estimation error was less than 2 ∘C for a maximum temperature of the BGA within 100 ∘C, and less than 4.5 ∘C for temperatures greater than 100 ∘C.