TO220 Heatsink

Thread Starter

selfbg

Joined Jun 11, 2010
23
I cant find anywhere heat sink for TO220 with the spec:
The total power is ~70W.
So "theta" sink-to-ambient = 0,92°C/W.

It doesn't matter natural or forced cooling.

Thanks in advance. :)
 

#12

Joined Nov 30, 2010
18,076
aavidthermalloy.com has heat sink calculators and air velocity calculators. That might lead you to a product that you can buy.
 

Thread Starter

selfbg

Joined Jun 11, 2010
23
I checked the site, but still can't find suitable heat sink.
 

crutschow

Joined Mar 14, 2008
23,155
For that much power a heatsink with an integrated fan would likely be best. Perhaps you can adapt a CPU cooler for PC to your needs such as one of these.
 

#12

Joined Nov 30, 2010
18,076
There is also the option of using a different (bigger) package. A TO-3 plus proper heat sink and fan might be smaller than a TO-220 with proper heat sink and fan.
 

Wendy

Joined Mar 24, 2008
21,840
I like the CPU heatsink/fan idea myself. You will have to drill/tap the holes yourself.
 

bountyhunter

Joined Sep 7, 2009
2,498
I cant find anywhere heat sink for TO220 with the spec:
The total power is ~70W.
So "theta" sink-to-ambient = 0,92°C/W.

It doesn't matter natural or forced cooling.

Thanks in advance. :)
To get 0.9C/W you need an extruded heatsink, very large and heavy. probably about 12" wide, 4" high.

BTW: if power dissipation forces the use of a heatsink < 1C/W, TO-220 devices are a poor choice. They have a theta of about 4C/W from junction to case. TO-3 is a much better choice.
 

bountyhunter

Joined Sep 7, 2009
2,498
There is also the option of using a different (bigger) package. A TO-3 plus proper heat sink and fan might be smaller than a TO-220 with proper heat sink and fan.
CORRECT. Thermal resistances add in series. The 4C/W junction-case of the TO-220 is MUCH larger than 0.9C/W. Going to the TO-3 which is <1C/W junction-case saves most of the total thermal resistance.
 
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