Thermal state of electronic assemblies applied to smart building equipped with QFN64 device subjected to natural convection

Abstract

The performance and reliability of electronic components and assemblies strongly depend on their thermal state. The knowledge of the temperature distribution throughout the assembly is therefore an essential element to ensure their correct operation. This is the main objective of this work that examines the case of a conventional assembly equipped with a quad flat non-lead QFN64 subjected to free convection. This active electronic package is welded on a PCB which may be inclined by an angle varying between 0°and 90°(horizontal and vertical positions respectively) and generates during its operation a high power ranging from 0.1 to 1 W. Thermoregulation of the assembly is ensured by natural convection, given its many well known advantages in this engineering field. Accurate relationships are proposed to determine the temperature on different areas of the device and the PCB. They are determined by means of a 3D numerical approach based on the finite volume method confirmed by measurements on an actual installation. These relationships allow reliability improvement of these electronic assemblies that are widely used in many engineering fields such as computing industry, mobile telephony, home automation, automotive, embarked electronics and the smart building applications considered in this work. The present survey complements a recent study which quantifies the natural convective heat transfer on the considered electronic assembly equipped with the QFN64 device, for the same power range and angle of inclination.

Surface temperature of electronic assemblies equipped with tilted and low-powered QFN64 subjected to free convection

“…This condition is difficult to achieve when the assembly is subject to natural convection given the weak convective heat transfer coefficients concerning the free areas of the QFN (top and sides). This is clearly shown by Baïri (2015a, 2016a) for the QFN16 model, by Baïri (2015b) and Baïri and Haddad (2016) for the QFN32, by Baïri (2015c, 2016b) for the wire bonded versions 16b and 32b, respectively, and by Baïri et al (2017) for the QFN64. These works are valid in wide ranges of the generated power up to 1W and for devices tilted between horizontal and vertical positions.…”

Cu-Al2O3 hybrid nanofluid natural convection in an inclined enclosure with wavy walls partially layered by porous medium

“…𝐸(𝑘) is the complete elliptic integral of the second kind. These geometries have been used in different engineering applications, such as micro-electronic devices, electronic packages, solar heaters, and other electronic equipment [1][2][3][4][5]. Whilst these configurations are of current use, limited attention has been devoted to them in the literature compared to the classical rectangular, square, and inclined walls geometries.…”