A linear isolation amplifier from Silicon Labs app note. Link here (PDF)
Analog circuits sometimes require linear (analog) signal isolation for safety, signal level shifting, and/or ground loop elimination. Linear signal isolation is typically difficult to implement, costly, and often exhibits mediocre performance. While the design community thirsts for a flexible and inexpensive linear isolator solution, it is the analog isolation amplifier (ISOamp) that most often captures the socket.
from Dangerous Prototypes https://ift.tt/2ExRd50