Stacking board level heatsinks

[rickmcinnis]

Has anyone ever considered or used a pair of the typical "board level heatsinks" for TO-220 devices to decrease thermal resistance?

Have an application that I would like to add a little insurance. Not enough space to use something else.

Figure one should use the thermal compound between and some kind of way to mechanically attach them - an unused hole in the bottom one and one on the top with some kind of strap with more thermal compound.

Could this work or its there something I am missing? If I did not think the latter was likely true I wouldn't ask!

Put in the photo for clarity. Random photo - only has one hole.

Thanks for any comments.

 

[sofaspud]

Use two heatsinks, each having a flat side, instead of battling the difficulties the example in the photo would create.
Attach two heatsinks front and back of the TO-220 tab with the same nut & bolt.

 

[rickmcinnis]

Thanks for the suggestion.

I should have mentioned there is no room for going in that direction and in another case two devices share the same heatsink.

 

[sofaspud]

Then I would look for one of the long rectangular heatsinks that fits between the fins of the one in the photo, e.g. DIP style, but a bit bigger. Or, well, get a better °C/W heatsink. Strapping vertically just wouldn't be near the top of the list of options I'd consider.

 

[mcandmar]

The contact area between them is so small i doubt stacking them would do much. They do come in different heights, for example Aavid makes 60mm tall version 530002B02500G - Board level heatsinks if you give us a better idea of your application we may have some ideas..

 

[rickmcinnis]

Thanks for the help. Already using 60 mm tall ones. Just wanted to allow for a little extra margin but looks like that is not the way.