[time-nuts] low noise voltage regulation, again

Scott Burris slburris at gmail.com
Thu Feb 18 03:57:47 UTC 2010

I'm finally thinking about building some real power supplies for my 
and LPRO-101, and that got me thinking about the topic of low noise power
supplies again.

I think Dr. Bruce and I exchanged some messages about this a year or two 
when I was looking at "RF regulators" and the conclusion seemed to be that
the ancient ua723 was still the low noise champ.  Is that still the case, or
are there better modern regulators?

I was thinking of doing strictly linear regulators, but then I read this
note at Wenzel:


I think of this as the "short out the noise before anyone sees it" approach.
Do you think the circuit of figure 4 can clean up the output of a 
switching regulator
down to 20nv?  I assume this was written as a post cleanup of a linear 

Alternatively, what do you think about these Maxim circuit ideas which claim
7nv and 6nv:


Is it better to apply cleanup circuits like this to average regulators or
go back to something derived from the 723 or its kin?

Just casting about for ideas about what I should be experimenting with.


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