[hpsdr] How much -12V? Was Re: Power supplies, again

[michael taylor]

I don't know much about the Janus and Ozy boards, and haven't looked
at their design closely because the high speed digital design is well
beyond my modest electronics understanding, but as far as I know the
-12V is not used in as a power source for digital logic, but as a
power source or reference for op-amps and maybe ADC/DAC.

My wild out-of-the-blue guessing is that 100ma is about all you should
need for -12V voltage rail. So I suspect the PicoPSU power supply
should be adequate power handling, but I won't guess on its noise
level.


On 5/13/07, Doug Faunt N6TQS +1-510-655-8604 <faunt at panix.com> wrote:
>
> Can some of the other designers comment on how much -12V other boards
> are likely to use?


>    Date: 11 May 2007 21:28:55 -0400
>    From: Doug Faunt N6TQS +1-510-655-8604 <faunt at panix.com>
>
>    Hm, the 60W picoPSU seems to be rated for 50ma at -12V.  Even the 120W
>    unit has a max rating of 100ma.
>
>    73, doug
>
>       Date: Fri, 11 May 2007 20:19:05 -0500
>       From: Bill Tracey <bill at ewjt.com>
>
>       Current draw I'm seeing with Ozy/Janus playing radio with an SDR 1000 is:
>
>       +12v: 200 ma
>       +5v: 180 ma
>       -12v: 70 ma

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