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SMD Via hole design-thermal performance

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#72848

SMD Via hole design-thermal performance | 3 October, 2014

Does anyone well know in "via hole design in ground pad" I have few question that i want to know the answer,thanks.

1.Thermal performance compare about a.Via Full Stuff (top/bottom:solder mask and inside is air) b.Via Half Stuff (bottom:solder mask,top open,so solder paste will stuff the hole)

2.Via hole number compare with thermal test

Does any paper or information about those question? Thanks for your help and wish you have a nice day!

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#72985

SMD Via hole design-thermal performance | 30 October, 2014

No paper thing, while I can make some suggestions based on my experience.

what is the size of your via? If it's smaller than dia0.4mm, in PCB production process it should be filled by soldermask. So my suggestion is design it to be full filled by SM, thus the solder paste would not flow inside the hole. The thermal performance is nothing with the air or solder, just the hole wall copper thickness. Make a specification of hole wall copper thickness, 25um min or more.

And then, you should make more via holes, the more the better to thermal porformance.

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#72992

SMD Via hole design-thermal performance | 31 October, 2014

I do not recommend ever leaving the top of a via-in-pad open. Cap the via in the pad. Leaving it open for "solder to stuff the hole" causes issues in assembly, notably insufficient solder due to vampirism (the solder wicks into the via, rather than forming the bond).

cheers, ..rob

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#72995

SMD Via hole design-thermal performance | 1 November, 2014

Papers: GOOGLE thermal pad via

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#74228

SMD Via hole design-thermal performance | 15 July, 2015

If it is important to have vias within thermal pads to help dissipate heat i would recommend using solder mask to stop the solder from wicking down the holes and resulting in insufficient solder. Some further info can be found here:- http://www.surfacemountprocess.com/design-for-manufacture.html

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