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PCB layout techniques to maximize power module performance

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mdavismarsh
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re: PCB layout techniques to maximize power module performance
mdavismarsh   8/27/2010 3:09:48 PM
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Solder wicking is definitly a problem when the size of a via increases. The advice I received from an assembly house was to keep the vias under 12mils (0.305mm). However the cost increases as vias go below 10mil. So as a general rule of thumb, I keep most thermal vias at 12mil, and only go to 10mil and under for small packages like LLP.

_hm
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re: PCB layout techniques to maximize power module performance
_hm   8/23/2010 2:25:58 PM
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I always liked NSC application notes as continuing education tools and this article also adds to it. Design / simulation tools on NSC web site also gives engineer kick start for new design. However, I may like to see following: More advance simulation tools with detailed parts modeling for both active and passive parts. Simulation result should also generate comprehensive report with basic logic, formulas for the calculation and optimization techniques. Second important part is measurement and verification of this simulated result with actual fabricated CCA. Many a time real time measured results are significantly different from simulated results and may not be acceptable. Can the parts manufacturer or Test and Measurement equipment manufacturers provide more educating tutorial on these aspects? e.g. basic for EMI/EMC limits, their measurement techniques and required tools, simplified ways for thermal measurement? We also need information about long term reliability for all consumer, industrial and military applications, likely failure modes in harsh operating environment. With this information engineer may be able to make better design instead of cook book type approach.

Borge
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re: PCB layout techniques to maximize power module performance
Borge   8/23/2010 9:40:54 AM
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Thanks for an interesting article! My own experience from years of PCB layout is that the hardest tracks to lay out are those you don't see. Very frequently, the return current will pass in a large ground plane which is only added after all placement and routing are done. It is very important to save space which the ground plane will occupy and think about the return current paths in areas where no components or tracks are yet placed.

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