28 Feb
2009
28 Feb
'09
9:07 a.m.
Chuck Guzis wrote:
All of the S100 boards I've seen use simple linear
regulators, so you
need some headroom--but not too much. A lot of S100 7805s and LM323-
5s were operated within an inch of their maximum current ratings
(some had bypass resistors installed) and generated a lot of heat. I
wouldn't run the supply rails any higher than I had to.
Cheers,
Chuck
The Sol-20 had an app note about this problem. Apparently they shipped
them for a while with transformers that were out of spec with the end
result that the unregulated power ran high. The recommended fix was to
take a power bridge, mount it to the case, and wire it in series with
the positive voltage run in order to get a ~1.4V drop.