Ken Shirriff writes:
I saw an ad for a tiny chip1 that provides 5 volts2 of isolated power: You feed 5 volts in one side, and get 5 volts out the other side. What makes this remarkable is that the two sides can have up to 5000 volts between them. This chip contains a DC-DC converter and a tiny isolation transformer so there’s no direct electrical connection from one side to the other. I was amazed that they could fit all this into a package smaller than your fingernail, so I decided to take a look inside.
See the full details at righto.com.