[hpsdr] HPSDR power supply design

[Michael Ardai]

I have started to design a linear supply for the HPSDR and
am trying to guess on how much current to provide.  A previous
post states that Janus/Ozy pull 200mA at +12, 70mA at -12,
and 180mA at +5.  I am wondering how the other cards will
compare to this.  Also, it looks like everyone is generating
3.3V onboard from 5V; will there be much demand for 3.3V
directly on the backplane?

I am looking at using the LM1084 regulators for the positive
rails and the LT1185 for the -12V.  Depending on how much we
plan to draw from +5 and +3.3, it will likely make sense to use
two transformers to keep the thermal issues under control.

/mike