Temperature determination of tilted electronic assemblies equipped with basic and wire-bonded QFN16 and 32 devices subjected to free convection

Abstract

The correlations proposed in this work allow to calculate the average temperature on different areas of electronic assemblies containing basic QFN16 and QFN32 packages and their wire-bonded versions named QFN16b and QFN32b respectively. The study is based on correlations proposed in recent works allowing calculation of the average natural convective heat transfer coefficient according to the power generated by the package and the tilt angle of the printed circuit board (PCB) on which they are welded. The considered generated power is within the range 0.1–1W for the QFN16 and 16b models. For the QFN32 and QFN32b, the correlations are extended to lower power ranging from 0 (off) to 0.1W. These power ranges are associated to an inclination angle of the PCB varying between 0° and 90° (horizontal and vertical positions respectively) corresponding to the operative conditions of these devices increasingly used in electronics. Temperature determination of every part of these assemblies through the proposed correlations easy to use, helps improving their thermal design and reliability.