I have a requirement for a 60 volt rail in a device powered from a nominal 5 volts..  The load on the 60 volt rail will be pretty small, around 0.5mA.  The important requirements are :

1) Must be very electrically quiet, which would seem to rule out a classic switching converter.
2) Be physically small.  I can't accomodate any large transformers.  Surface mount inductors are ok.

I'm thinking that some kind of resonant converter may be the way forward, but my knowedge of power conversion theory isn't exactly great.  I'd appreciate any ideas you may have.  I don't mind having to use a linear post-regulator after the converter to get a stable supply.

Cheers

Mike Rigby-Jones