Investigation of thermal modes of a microwave power amplifier in the SMD version

The article presents the results of a numerical study of the thermal regimes of a microwave power amplifier housed in an SMD package, aimed at assessing the influence of the package design parameters on heat sink efficiency and the maximum temperature of the active region of the die. The relevance of the study is due to the increasing power dissipation density in microwave electronic devices, which leads to higher thermal loads on semiconductor devices and their packages. Given the limited heat dissipation capabilities, standard QFN package designs do not always provide the required thermal regime, reducing the reliability and stability of power amplifiers. The aim of this work is to investigate the effect of the SMD package configuration on the thermal regime of a microwave power amplifier and to identify design solutions that reduce the maximum temperature of the active region of the die at a given dissipated power. A numerical study of the thermal regimes of a microwave power amplifier was performed for various SMD package configurations. Based on a steady-state heat transfer model using a specified heat dissipation model, temperature fields were obtained for several structural package variants. Quantitative relationships between package configuration parameters and the maximum die temperature are established. It is also shown that the use of thermal vias and placing the metal base of the package in a cutout of the printed circuit board can significantly reduce the thermal resistance of the heat conduction path. The obtained results enable a well-reasoned choice of the SMD package configuration for microwave power amplifiers based on the active heat dissipation area of a specific die, in order to lower the maximum operating temperature without changing the package type or mounting technology. The presented results can be used in the early stages of semiconductor device design to reduce the number of numerical and field experiments and to improve the reliability of microwave devices.

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