Effects of the Encapsulating Resin on the Junction Temperature of the QFN16 and QFN32 Electronic Packages Subjected to Free Convection

ABSTRACT

The junction temperature of the quad flat no-lead with 16 and 32 leads (QFN16 and QFN32) electronic packages subjected to free convection is highly affected by their encapsulating resin's thermal conductivity. This study considers a variation of this conductivity between −80% and +100% of the average value measured on an industrial prototype by means of the Transient Plane Source method. The three dimensional numerical solution based on the control volume formulation shows that the thermal trend is of exponential type for these components but with different functions. The proposed relationships allow the calculation of the junction temperature of both QFN16 and QFN32 according to the power generated varying between 0.1 and 1W, and the inclinations relative to the horizontal plane in the range 0–90° (horizontal and vertical positions respectively). The law governing the influence of conductivity on the junction temperature shows that a more conductive resin does not significantly lower the junction temperature. However, for low conductivity values, the temperature can exceed the maximum recommended by the manufacturers, causing possible malfunction of the QFN and altering its technical performance that are directly related to its thermal state. In some cases, the device can be decommissioned.

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Notes on contributors

Abderrahmane Baïri

Abderrahmane Baïri is Professor at the University of Paris and Head of Heat and Mass Transfer Laboratory. His main teaching activities are related to heat transfer, experimental techniques, and numerical methods. His research is carried out in the Laboratoire de Thermique Interfaces Environnement (LTIE) and deals with natural convection, heat transfer at solid-solid interfaces and thermal characterization of materials.

Oriana Haddad

Oriana Haddad is a PhD student at the University of Paris 10, in Ville d'Avray. She received her Research Master degree in 2014 in the speciality Energetics and Environment at the University of Paris 6 Pierre and Marie Curie, Paris. She teaches heat transfer and thermal metrology in the Thermal and Energy Engineering Department (Génie Thermique et Energie) of Ville d'Avray. Her research activities in Laboratoire de Thermique Interfaces Environnement (LTIE, University of Paris) deal with convective heat transfer, nanofluids, and thermal characterization of materials.

Jean-Pascal Guinart

Jean-Pascal Guinart is Assistant Engineer, Technical Manager in the Department of Thermal and Energy Engineering (Génie Thermique et Energie) of Marne La Vallée University. He received his Research Master degree in 2010 in the speciality “Energetics, Aeronautical and Terrestrial Propulsions, Environment (EPATE)” at University of Paris 10, Ville d'Avray. He obtained in 1988 a Master degree in “Applied Physics, Engineering Electronics and Automatics” at Montpellier University. He participates in the research activities in Laboratoire de Thermique Interfaces Environnement (LTIE, University of Paris 10) mainly in thermal and electrical measurement techniques, IR thermography and TPS thermal characterization of materials.

Kemi Adeyeye

Kemi Adeyeye is Associate Professor / Senior lecturer in Integrated Design and Architecture at the University of Bath with expertise in architectural design, architectural technology, integrated design, energy saving and information systems. She is member of the Centre for Advanced Studies in Architecture (CASA), specialized in Integrated Design: Architecture, Technology, Resilience and Sustainability. She is a chartered member of the Chartered Institute of Architectural Technologists (CIAT), and the Royal Institution of Chartered Surveyors (RICS). She established and leads the Water Efficiency Network. She also edited the recently published book on Water Efficiency in Buildings: Theory and Practice.

Nacim Alilat

Nacim Alilat is Associate Professor / Maître de Conférences in Energetics at the University of Paris 10. He obtained his PhD degree in Energetics speciality at the University of Paris 10 in 2004. He teaches heat transfer, experimental techniques and numerical methods in Thermal and Energy Engineering Department (Génie Thermique et Energie) of Ville d'Avray. His research activity in the Laboratoire de Thermique Interfaces Environnement (LTIE, University of Paris 10) is mainly focused on heat transfer at interfaces, convection and thermal characterization of materials. He is the head of the numerical modeling Laboratory.