You didnt specify isolation voltage;
but maybe have a look at
h**p://focus.ti.com/docs/prod/folders/print/dcp010505b.html
h**p://focus.ti.com/docs/prod/folders/print/dch010505s.html
Thank you but their cost ($5.35) are problem for me. I mean a simple oscillator, transformer, some diodes and a 7805? Total cost should be around $1, for 60K pieces/year. I need isolation voltage 4000Vrms. I think it is related with transformer.