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modularlogix wrote:

Hey guys, was wondering if someone could suggest active heatsinks for the Virtex 5 27mmx27mm 665 package (or if you used one on the 676 V4 package).  I'm hitting 92C on a design and am having a difficult time finding a heatsink with a fan in this small package size.

 

Thanks,

Dan 

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Heat pipe?

Radian Heatsinks has a line of Fansinks.  

This one is for a 27x27mm package

http://www.radianheatsinks.com/index.php?act=viewProd&productId=406

That looks very interesting.  It's hard to find good heatsinks that don't require a lot of keepout area

around the package and / or large mounting holes in the PC board.  It looks like the board in the

picture actually violates the recommended keepout area.  Note that the JTAG connector is not

populated and the Altera part seems to be under the clip.

Regards,

Gabor

That looks like a good product, thanks.

Unfortunately the keep out doesn't work great for me, boards are already being built that don't have the clearance for their snap-on attachment.  That should be able to be figured out though. 

If you really have no room for clips, you might look at a stick-on style heat sink.  It looks like

the fan in this heatsink is just screwen on top of a standard extruded-fin style heatsink.  We

have built many thousands of boards with heatsinks glued onto the BGA components.  Generally

an epoxy-based thermal glue works better than any of the peel-and-stick varieties, but there

are some of those that work on the right kind of  BGA's.  I have found that the stick-on can

work for BGA's with a very flat metal top like Xilinx flip-chip packages.  They're pretty

much useless on the rounded-bubble-top parts like the FBGA-456 package.  However we

have used the epoxy approach on those BGA's with no problems.  We have not however

attached fans to them.  Now if someone would just make a PC chassis that actually has

airflow around the plug-in cards we'd all be in business. :)

regards,

Gabor

Thanks Gabor,

I have clearance on 3 sides just not the 4th, and actually have pin holes for a Aavid push-pin design; its just hard to predictively support every heat sink ever made :) 

I did notice that an adhesive pad was an option when ordering that particular heatsink; the epoxy idea could work as well.

Thanks for the ideas.

Dan 

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modularlogix wrote:

That looks like a good product, thanks.

 

Unfortunately the keep out doesn't work great for me, boards are already being built that don't have the clearance for their snap-on attachment.  That should be able to be figured out though. 

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There are various thermal epoxies that you can use to permanently attach a heat sink to the device.