On Jun 23, 2005, at 2:30 AM, David P Harris wrote:

>> ack" switching regulator, in a 3-terminal configuration...
>
> How big is this circuit board?  Looks about 0.8 x 1 inch.  Would a smd 
> one approach the size of a TO220?
>
Yeah, about .7x.9 inch :-)  I have an SMD layout, but it's not much 
smaller,
though that becomes highly dependent on which packages you think you can
manage to solder.  It turns out that an SOT23 transistor has close to 
the
same footprint a TO92, and a 1206 resistor about the same footprint
as a vertical TH resistor (though of course they're much THINNER.)
And inductor/capacitor size in SMT is pretty variable depending on how
much you're willing to pay.  (The black regulator isn't designed for the
low inductances of vert small SMT parts.)  You get some space
back going to double sided as well.

OTOH, I figure the board as shown is already pretty close the the 
average
TO220 plus smallish heatsink...

BillW
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