[Amps] ARF1505

[Carcia, Francis A HS]

A very smart thermal guy once told me the effective radius of a copper
spreader is 10 times the thickness. 

-----Original Message-----
From: Will Matney [mailto:craxd1 at ezwv.com]
Sent: Friday, May 20, 2005 4:57 PM
To: amps at contesting.com
Subject: Re: [Amps] ARF1505


I think they mentioned using a copper spreader plate because of this in the
literature. The part itself, where it hits the heatsink is about 1-1/16" X
1-1/16" square. That's a good bit of concentrated heat. I would think one
would need at least a 3/8" thick top on the heatsink, maybe more so it wont
heat up as fast. The 1/4" thick types I doubt would stay cool long enough as
there's 750 watts of power going into it in heat, the other 750 out to the
load. If using the 1/4" sink, one would most likely need a 1/4" thick copper
plate on top or a little thicker piece of aluminum plate. There's water
cooled copper blocks for this too.

Best,

Will

*********** REPLY SEPARATOR  ***********

On 5/20/05 at 1:40 PM Dan Levin wrote:

>> Has anyone tried the ARF1505 FET in any solid state amps yet?
>
>Cooling a 750 watt point source is a major problem.
>
>One is almost certainly better off (in a ham application) using
>several smaller parts (ARF463 e.g.) - which will require more
>circuitry but will allow much easier cooling.
>
>                  ***dan, K6IF
>
>Join us for the California QSO Party, Oct. 1-2!
>
>
>
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