AVR-Chat

Hi Tim
 
I just had a quick look. As you have the pad for the tab and then thermal
reliefs out to the plane, I am not sure you are going to get as good a heat
transfer as you would expect. The whole idea of thermal reliefs is to enable
good soldering by reducing the amount of heat lost out to the plane so the
opposite effect will take place with heat from the device.
 
Would you not be better to put the thermal plane on the opposite side and
use a lot of via's in the pad of the tab itself. Similar to what you do with
those IC's with a thermal pad on the underside of the component? 
 
I have done this very thing with power supply IC's where I place the thermal
pad between the pads for the pins, and then lay down as many small vias as I
can. I then lay down a thermal plane on the opposite side of the PCB which
is connected bya the vias. This has worked very well for me in the past.
 
 
Dave...
---
Very funny Scotty, now beam down my clothes!!!
---


 
From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of tim gilbert
Sent: 02 February 2011 23:11
To: AVR-Chat@yahoogroups.com
Subject: Re: [AVR-Chat] d2pak heat sink
 
  
Steve,
I can't attach or upload a pdf so I've added an image to a photo album named
"JEM Innovation".

Tim




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