Heatsing for TO263

Reduces the board area required for thermal pours, and will work slightly better. Their claims about better thermal performance look like snake oil--theta will be dominated by the copper pour.

Cheers

Phil Hobbs

Look at the competition - same issue.

The AAVID parts are tinned copper and patented up the wazzoo.

It would likely make more sense to turn the TO220 around, fix it to the extrusion, and then reflow the extrusion to the board.

..but then it wouldn't be a refow-only assembly.

Fabs are allergic to mechanical fasteners.

RL

Yes, good idea. One idea, leave a bit of final hand work, for after the automated assembly step.

We use these,

similar idea. You need a topside copper pour to transfer heat from the dpak tab to the heat sink. That might be in the ballpark of 5 K/w, so adds to the overall theta some.

What do those things cost? The hype level on the data sheet is high. There is no data below 200 fpm air flow, and the theta numbers look optimistic. All those tiny fins are useless at low air flow. The digs at Aavid are absurd.

You can get pretty good dpak cooling by coupling through vias into pcb planes, and that's free.

form the leads for inverted surace mount reflow the TO220 onto the heatsink. reflow the assembly onto the board.

or place the TO220, place extra paste on the tab place the heatsink on the tab.

not needed

the problem is getting DPAK with the leads bent away from the tab

This non-isolated buck module places the beastink at the other end of a bunch of vias:

It looks interesting

I would perhaps be a little worried about if the heatsink reaches the correct temperature to enable correct soldering of both the heatsink and the SMD device

Cheers

Klaus

• Woah! Will it take off and fly?