Online proceedings - EDA Publishing Association

24-26 September 2008, Rome, ItalyCFD for Electronics Cooling: MCAD and EDAEmbedded vs. Stand-aloneJohn D. ParryMentor Graphics Corporation Mechanical Analysis Division81 Bridge Road, East MoleseySurrey, KT8 9HH, UKAbstract–Computational Fluid Dynamics (CFD) forElectronics Cooling (EC) has developed differently fromgeneral-purpose CFD, due to the nature of the market it serves.The benefits are clear – the use of EC CFD in product designhas had a profound impact on both time-to-market and cost.Today the EC CFD market is dominated by suites ofapplication-specific codes, focused at the different packaginglevels: system-, board- and package-. Their usage maps ontocurrent product design flows at different stages in the productcreation process, from IC package to equipment design.Interfacing with EDA and MCAD software has helped theirincorporation into existing in-house design practices. MCADembeddedCFD software is gaining popularity and being soldeffectively by MCAD vendors for general-purpose applications.EDA vendors are again taking an interest in thermal design.This invited paper considers the future of EC CFD and theprospects for stand-alone software vs. mechanical CADembeddedand EDA-embedded solutions. This is considered inthe context of how today’s EC market has developed over time,and the unique requirements placed on EC CFD tools.The challenges of both MCAD and EDA embedded EC CFDare discussed from both technical and business standpoints.I. INTRODUCTIONIt’s worth reflecting on the impact EC CFD has had on thethermal design of electronic products. Companies that useEC CFD have been independently found to complete thermaldesign verification almost 3 times faster than those thatdon’t, as shown in Fig. 1 [1].To get an understanding of how this has been achievedand the prospects for the future, we need to look at howtoday’s EC CFD market has developed.II. HISTORY OF CFD IN ELECTRONICS COOLINGWhat follows is by nature anecdotal, being unavailable asarchival material, but comes from the memories of severalpeople involved with EC CFD from the outset. It is anabridged version of events, presenting only what is mostpertinent to the topic of this paper, in roughly chronologicalorder.1970s & 80s: 1974 saw the foundation of CHAM Ltd., thefirst commercial company to provide a CFD consultancyservice, and later software, to industry. PHOENICS debutedin 1981 as the first commercially available software tool inCFD [2]. Electronic Design Automation also dates back tothe beginning of the 1980s, when Daisy Systems, MentorGraphics Corporation and Valid Logic Systems were allformed. Creare Inc. launched the first version of Fluent in1983. The use of commercial CFD codes in electronics datesback to the mid to late 1980s when Dereje Agonaferintroduced a number of licenses of PHOENICS into IBMPoughkeepsie. At around the same time Fluent from Crearewas being used by DEC. The mid 1980s saw rapid growth inchip power in the bipolar-based digital circuitry of the day,as Fig. 2 shows [3]. The mid to late 1980s saw theemergence of PCB thermal design tools. One of the first wasPCBTHERMAL from Pacific Numerix.% Design time spent on ThermalVerificationFig. 1: Proportion of Total Design Time taken to Verify Thermal DesignFig. 2: Growth of Bipolar and CMOS Module Heat Flux©EDA Publishing/THERMINIC 2008 1ISBN: 978-2-35500-008-9