[Amps] Ldmos heat spreaders

[Steve Wright]

On 16/08/16 01:45,  Ian Swain <insane.swain at gmail.com> wrote:
> Hi guys I'm building my first ldmos amp with a blf188xr and can't find a
> nice think slab of copper for a heat spreader
>
> I've only found up to 6mm think would this be okay ? Or could I get away
> with 2 layers to get 12 mm with heat transfer paste ?
>

I've bought 12mm copper bar from Steeltech on Te Tahi street.

Heat transfer is more about the minimum number of interfaces and a 
proper fit - than the best-best material.  Which means, a machined 
glossy-dead-flat aluminium surface is going to work better than a poor 
copper surface.

You CAN get the MOSFET soldered to an aluminium heatsink - they use an 
ultrasonic soldering tool and the results are superlative.

There is also the option of water-cooling an alloy block.  This is a 
little more fiddly in the cooling department, but quite a lot simpler in 
the mounting department.

Steve