Free convective overall heat transfer coefficient on inclined electronic assembly with active QFN16 package

Abstract

Purpose – The purpose of this paper is to determine the overall free convective heat transfer coefficient for an assembly constituted by a Quad Flat Non-lead QFN16 welded on a Printed Circuit Board (PCB) which may be inclined with respect to the horizontal plane by an angle varying between 0° and 90° corresponding to the horizontal and vertical position, respectively. This electronic device widely used in electronics generates during its effective operation a power ranging from 0.1 to 0.8 W. The assembly is installed in an air-filled cavity. Design/methodology/approach – Calculations are done by means of the finite volume method for many configurations obtained by varying the generated power, the inclination angle and the position of the QFN16 on the PCB. The dynamic and thermal aspects are presented and commented. Findings – The study shows that the thermal state of the electronic device is influenced by the previous three physical parameters. A correlation between the global convective exchange coefficient, the generated power and the PCB inclination angle is proposed in this survey. Practical implications – The results of this survey allow a better thermal control of this conventional arrangement widely used in electronic applications. Originality/value – The correlations proposed in this work are original and unpublished. The considered power varies between 0.1 and 0.8W corresponding to the effective operation of the device, associated to a PCB inclination angle ranging between 0° and 90°.