Homebrew PCBs

>unfortunately the parts I am describing have a heat slug under the 
>part and are designed to be soldered to the PCB.

If I followed the datasheet for the heatsinked component in the shot 
then there would have to be 24 vias connecting the bottom 8 sq. cm 
pad to the top 3 sq. cm pad to which the slug is soldered.

>Once the parts are soldered down, there is no access to the heat
>tab, thermal dissapation is only thru the PCB.

The case is always a viable means of heat dissipation, albeit with 
higher junction-to-whatever thermal resistance. Couple the case to a 
suitable heatsink and your junction-to-ambient resistance can be more 
than suitable.



--- In Homebrew_PCBs@yahoogroups.com, "Dave Miller" <dmiller45@...> 
wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, "derekhawkins" <eldata@> 
wrote:
> >
> > >Has any one else had to use similar parts? How have you managed 
to 
> get
> > >the heat out of these parts? Any other suggestions?
> > 
> > Double sided thermal tape (or thermal epoxy) and heatsink.
> > 
> > http://www.pbase.com/eldata/image/66582088
> > 
> > 
> > --- In Homebrew_PCBs@yahoogroups.com, "Dave Miller" <dmiller45@> 
> > wrote:
> > >
> >
> 
> Thanks Derek, the method you describes works great for parts where 
you 
> have access to the heat tabs, unfortunately the parts I am 
describing 
> have a heat slug under the part and are designed to be soldered to 
the 
> PCB. Once the parts are soldered down, there is no access to the 
heat 
> tab, thermal dissapation is only thru the PCB.
>