Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Gap pad W/m.K (thermal conductivity)

cupoftea

Advanced Member level 5
Joined
Jun 13, 2021
Messages
2,704
Helped
54
Reputation
108
Reaction score
116
Trophy points
63
Activity points
14,293
Hi,
We have a piece of gap pad 2.5mm thick to get heat from case top of SOT223 to metal enclosure.
The gap pad has thermal conductivity of 1 W/m.k
Aluminium has 247 W/m.K.

So basically, we can say that our Thermal resistance across the gap pad, will be 247 times worse than what it would be if the gap pad was of aluminium.
Would you agree?
 
You can do better with gap pads, the 1W/mK is pretty lame.
But if you must have voltage standoff then you are looking at
either a silicone (maybe loaded) or the aluminum nitride slabs
(not compliant, but 100W/mK). Graphite seems semi-decent
too but won't stand off anything. Maybe you get as thin a soft
piece for both faces crush-fit, and mostly AlN slab, if you need
voltage (if no voltage, then use the damn aluminum if you're
too cheap for copper).
 
Hi,
Thanks, and we have 1W of dissipation per SOT223 transistor.....the area of gap pad on it is approx 1.5cm^2. The distance is 2.5mm

so taking 1 W.m/m^2.K

.that means we get 16.7 kelvin drop across the gap pad. Would you agree?
 

LaTeX Commands Quick-Menu:

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top