%0 Conference Proceedings
%4 sid.inpe.br/mtc-m19/2011/08.02.13.06
%2 sid.inpe.br/mtc-m19/2011/08.02.13.06.32
%@issn 2236-2606
%T Simulation Method for Effective Thermal Conductivity Determination of Complex Boards
%D 2011
%A Costa, Rafael Lopes,
%A Vlassov, Valeri,
%@affiliation
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%B Workshop em Engenharia e Tecnologia Espaciais, 2 (WETE).
%C São José dos Campos
%8 3 - 4 maio
%I INPE
%J São José dos Campos
%S Anais
%1 INPE
%K Mecânica e Controle Orbital, Effective thermal conductivity, PCB.
%X Resistors, capacitors, transistors, and LEDs are components used in electronic systems, normally assembled to printed circuit boards PCBs. Such components generate heat in operation which must be conducted away efficiently to frames where the board is fixed. The components operating temperatures depend on heat dissipation rate, mounting technology, component placement and finally effective thermal conductivity of the PCB. The temperature of some components may reach about 100º C while the PCB frame is kept at near-ambient constant temperature. The reliability of electronic components is directly related to operating temperature. Hence, a correct temperature prediction shall be provided by the thermal project of the board under the hottest operation conditions. The PCB effective thermal conductivity is a significant parameter which influences the component temperature and its determination for complex multi-layer PCBs is not a simple task. In space applications, the only way to spread and reject heat of electronic equipments is by thermal conduction once there is no air available to apply convectionbased cooling systems such as heat sinks and fans. In this paper we present a simulation method used to determine the effective thermal conductivity of multi-layered boards. Such method uses a CAD based thermal model builder named SINDA/FLUINT Thermal Desktop and aims to determine the effective conductivity of a PCB by comparison between a detailed multi-layered anisotropic model and an equivalent homogeneous model. The method was applied for PCB-frame configurations typical for space applications. The simulation outcomes were compared to the values of effective conductivity obtained by analytical methods. Besides, a sensitivity analysis is performed on variations in component mounting technology and PCB layers placement. The results are discussed in a way of evaluation of applicability of existing methods and estimation of inherent uncertainty of PCB thermal effective conductivity determination.
%@language en
%3 1307.pdf