>> that was without the magnetics, which will be the expensive part.

> The problem with most isolated DC-DC converters is that they end up  
> using some custom-made transformer designed for optimal efficiency in  
> exactly that circuit.  Surely there has to be SOME standard low-cost  
> magnetic component suitable for <50mA worth of power isolation?   

A couple years ago, I did a project that included an embedded
modem & DAA.  The DAA requires isolation to meet FCC specs.

It was a Conexant CX81300 SmartACF single chip modem with CX20493
SmartDAA (their document 102260B).  The reference design included
an inexpensive DC-DC converter.  The hardware guy didn't have any
trouble sourcing the transformer.

You might want to look at modem chips as their reference designs
may address this requirement and have a suggested parts list.

						Lee Jones


-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist