>From a 2012 discussion on time-nuts by M. Simon and Voker Esper: <http://www.edn.com/design/analog/4394761/Successful-PCB-grounding-with-mixed-signal-chips---Part-1--Principles-of-current-flow>
There are 3 parts to the article - links are available at the end of every section to the next section. On Wed, Jun 24, 2015 at 11:54 PM, Neil Schroeder <gign...@gmail.com> wrote: > Lets take a hypothetical device, like specifically a PRS10, but could be > any time/freq device like a PLL or an amplifier or all of these. > > Isolating power supplies with some dexterity can greatly improve noise > control, and less peformance related, can help us protect very very > expensive circuits from their less bourgeois support ICs. Many of us may > choose to implement them as modular devices for easy relocation or > replacement. > > Main question: if I want to isolate the quiet and noisy power supplies, or > just supply them differently, can they share a common return? > > The basic answer has to be yes. Eventually everything has to get back to > ground, and the Earth itself is a fair equalizer of all things on it. I > can clearly join analog and digital back at the input supply. But if I had > them isolated, do those iso grounds have to stay with their iso supplies? > > Take the PRS10 - it has two cables for Vin - power and signal supplies - > but only one return cable. Can i isolate, via transformers couplers what > have you the two supplies yet return the common ground to one or the other? > > The signals handle themselves - they each have a ground wire of their own, > or does that handle it ? Are each of those opportunities for a loop? > > I know it'd work with just keeping separate DVcc and AVcc supplies that > join at some point, and then that return can join at the star ground like > everyone else. If you are designing the module, you can handle the > isolation inside and just have one input supply and return then isolate new > supplies internally and eliminate the second cable. Or two in vcc, two out > gnd. Those all make sense. > > I think the single return option on the PRS10 is what's hanging me up > here. > > Does isolation offer any real further benefit than AVxx and DVxx that is > even worth pursuing outside the extreme use cases? > > Lots of words. Thanks. > > NS > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.