[Amps] FET cases / heat sink

[Kevin]

Soldering an LDMOS FET onto/into a copper spreader is not difficult.

W6PQL has a video of the process on his site. A heating plate is used to 
bring the copper spreader up to temperature.

Once soldered there is no requirement to re-tighten mounting hardware 
after so many hours of operation nor is there the possibility of 
snapping a screw off in the spreader or God forbid cracking the device 
with too much torque.


On 1/2/2017 12:03 PM, Scott, Christopher wrote:
> I know that Manfred and others on this list have advanced thermodynamics knowledge - and hope to explore a curiosity of mine regarding high power amplifiers with the current 48 volt big fets.
>
> There is prevalent thought that unless one can significantly derate device power handling, bolted device to copper heat spreader connections are  quite inferior - soldering is best.  The device case to copper connection seems the weakest link.
>
> Why don't the manufacturers add another $3.00 worth of copper to the case size (and mass) to better spread the heat over more area (and slow the thermal time constant)?
>
> Wouldn't this greatly improve the functioning?  Wouldn't bolted mounting then work better?
>
> Chris Scott
>
> W4NEQ
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>

-- 
R. Kevin Stover
AC0H
ARRL
FISTS #11993
SKCC #215
NAQCC #3441


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