Sinking Heat From a Surface Mount Footprint to the Chassis

Artist · 2014-08-01T15:50:39+00:00

I am looking for ways to conduct heat from a copper surface on PCB to the chassis. My current plan is to do this with a #4 standoff. On the PCB I would use a Seastrom Manufacturing metal flat washer 5710-266-60 with their 5624-123-2 mica washer to electrically insulate from, and thermally bond to, the PCB. The heat would go through the mica washer, through the metal washer, through the #4 machine screw, through the standoff, and to the chassis. There are questions that came up as I designed the footprint for this. I am concerned about copper corrosion. Where heat is to be transferred from the copper through the mica I could leave the copper bare, cover it with solder mask, or put an opening in the paste mask for it so the copper would be tinned. Please advise me on which of these is preferable, or if there is another way. Is there a better alternative to the #4 mica washer such as a thermal pad material of the same shape and dimensions as that mica washer? I have seen thermal pads shaped like washers made for a DO-5 package, but they too large - twice the needed size. This is to sink heat from a Texas Instruments CSD17312Q5 MOSFET: Page 3 shows a recommended footprints for dissipating heat. I believe even the large one on the left will not be sufficient. So I want to conduct heat from that footprint to the chassis. -- To email me directly remove sj. in my email address.

Aug 01, 2014 83 Replies

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John Fields 11 years ago

You weren't talking objectively, you were offering platitudes disguised as profundities.

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John Fields 11 years ago

https://www.youtube.com/watch?v=qq8Rjex5Xy0 John Fields

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krw 11 years ago

Joined?

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krw 11 years ago

Fields checked out years ago.

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