On Fri, 12 Mar 2010 11:39:21 -0600, "Mark E. Skeels" said:
> I am working on a mixed signal system and I need to generate a smallish 
> negative voltage, (say -1V or so) for use as a negative op 
> amp/comparator supply to overcome problems like comparators not swinging 
> to ground, etc.
> 
> In the past, I have used ICL7660's or National LM2687, both work well; 
> solid enough and quiet enough, but they seem like overkill....does 
> anybody have a favorite, simple solution for something like this?

Hi Mark,

An unusual way is either with a photovoltaic optoisolator, or else use a
photodiodeor two with LED illumination. I know it's seems sort of
byzantine but it'll keep clocks out of your circuit.

Cheerful regards,

Bob



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