[PEDA] Thermal Impedance of Copper Areas

[Michael Salish]

Here is another trick that works for SMT parts. Place a copper pour on the  
reverse of the PCB not electrically connected to the power dissipating  
circuits on the other side. Don't solder mask this poured area. Then  
attach an aluminum bar (I use 6mm High x 25mm Wide x <as long as needed>)  
on the copper pour side using machine screws. This bar then mounts the PCB  
to some kind of enclosure or panel. The metal bar stiffens the PCB and  
removes a significant amount of heat to the cabinet or back panel. You  
would need to try your configuration to see if the Rth is low enough for  
this to work.

The bad news is you can't run tracks on the reverse side where the bar is  
located. We used this idea on a product and it allowed us to replace 2512  
parts with 2010 parts saving space and costs.

-- 
Mike Salish