Essais & Simulations n°127

mesures case Study

mesures case Study Simulated and Experimental component Temperature on the Intersil ISL8240 Evaluation Board There is not that much material public available comprising a consistent set of fabrication data and experimental results from which thermal board models can be built and compared. In a recent article Intersil’s J.Johnston [3] described the thermal behavior of a QFN package on a 4-layer evaluation board based on the vertical thermal resistance of the layer stack and the copper cladding in vias. Although we do not agree with his assumptions and conclusions a subsequent search for more data led us to a fine set of files and reports. Using them we created a ther- mal board model with TRM software and the results seem to fit quite nicely. The board under consideration is called ISL8240MEVAL4Z and can be found on Intersil’s home page at www. intersil.com. There is also a sister board with name ISL8240MEVAL3Z. The material The website [2] http://www.intersil.com/en/tools/referencedesigns/ isl8240mevalxz.html contains lots of documents and resources. Important for us are production data in “Design Files” The board under consideration. Size is 4” by 3” (Taranovich, 2015). The artwork Gerber files around the component look like this Download items. Thumbnails of the artwork. Search in the internet for ISL8240MEVAL4Z is leading to a report by Taranovich [4] where power considerations and (uncoated) infrared images of the board can be found. 38 IESSAIS & SIMULATIONS • N° 127 • Janvier-Février 2017

mesures board modeling We just paste some TRM input panes or output frames. Most of the input will be obvious. Board size is 4” by 3”. The finest structures in the layout are around 0.1mm. This is the lateral resolution which we demand for the results. No special materials are used. Taranovich is claiming 2 oz outer layers and 1 oz inner layers. The user guide claims 2 oz in all layers. Gerber files come from Cadence Allegro. 1 mil hole plating. Though-hole technology only. 957 drills. Excellon header has non-standard tools defi-nition and we corrected the header manually (in inch). For a graphical placement the Gerber file of the silk screen can be used. Gerber artwork of top layer 1 and outline of the component. A bulk material with k=10W/mK (“Comp_diel_loc$TRM”) is used. Component size is 18.8mm × 18.8mm. Summary of the model-build in TRM. ESSAIS & SIMULATIONS • N° 127 • Janvier-Février 2017 I39