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If your USB device ever suffers from noise caused by an earth loop or if you want to protect your PC against external voltages then you need a USB isolator.

If your USB device ever suffers from noise caused by an earth loop or if you want to protect your PC against external voltages then you need a USB isolator. The circuit described here offers an optimal electrical isolation of both the data lines as well as the supply lines between the PC and the USB device.The project itself is a spin-off from an earlier design for a portable oscilloscope for Android.
 
 
 

I propose a USB isolator. The data lines will be isolated with an ADuM3160. Power will be isolated by a flyback convertor. (using an LT3575 controller) What do you think?

Update:
I designed and buildt it, and it functions! The isolated flyback convertor took a bit of work, but it payed off, as the 5volt output looks cleaner on the oscilloscope than the input.

The top sticker design still needs some work, like using an undercase 'b' for the line speeds.

Update1:
The sticker is fixed.