Re: [Discuss-gnuradio] Maximum DC supply voltage for USRP

[Jeff Brower]

Marcus-

> What is the maximum DC supply voltage for the USRP?
> 
> I've been running it off of a 5V switched supply, but I wanted to move
> all power
>   supplies outside of the USRP cabinet that I have, so I'm using an
> external 13.8V
>   supply, with a LM7805 regulator.  The regulator is sagging due to high
> current
>   demand, so I'm thinking of supplying 13.8V directly to the USRP--is
> this safe?

The LT1085-3.3V linear regulator on the USRP is rated for 30V maximum input. 
However, nominal specs (voltage dropout, max current, etc) in the LT1085-3.3 
data
sheet are only given up to 8V input.  My suggestion would be to limit the input
supply to 8V.  The greater the delta between input and 3.3V the more excess 
power and
heat you are forcing the LT1085 to dissipate.

-Jeff