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7 Electrothermal Mechanical Stress Reference Design Flow for Printed Circuit Boards and Electronic Packages // / Stage 5. Temperature Post-processing in ANSYS Icepak SIwave lets you directly open the PCB design in Icepak where you can perform detailed post-processing operations on the board that exceed that shown above. Within Icepak, a report (see Figure 12) can be generated listing temperatures for the board and all the desired objects, along with the user- entered operating temperature limits f rom the manufacturer's datasheet. The report lets you confirm whether the board and objects are within the temperature limits. Components lying beyond these temperature limits are prone to damage. You can even specify arbitrary temperature limits. Objects that are above these limits will be flagged in red; marginal cases, where temperatures are within 5 percent of the safe operating limits, will be flagged in orange. You can also produce temperature maps for all the objects and the board as shown in Figure 13 for a natural convection (still air) thermal simulation. Heat sinks are added based on the selections in SIwave. Contour plots on a cut plane can also be generated in Icepak for the board and its components. In our board, these plots show that the heat is propagated downstream by the air flow away f rom the hottest components (see Figure 14). Additionally, Icepak lets you generate particle traces and vector plots (see Figure 15). Particle traces represent the path of hypothetical massless particles through the model. This path is calculated based on the computed flow field. Vector plots indicate the direction and speed of the air flow. Arrows in orange and red represent the fastest air flows. The length and direction of the vector represent the magnitude and direction of the velocity at a specific location in the PCB model. Figure 10. Icepak simulation setup in SIwave Figure 11. Thermal hot spots in SIwave Figure 12. Report dialog in Icepak

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