USB Host isolation

I want to use the ADuM4160 to isolate my USB host port but it is not clear whether it will work.  Can I do that?

  • The ADuM4160 USB isolator is designed to isolate a peripheral port and keep the port compatible with the USB-IF standard.  It does that job very well.  It was not intended for host isolation.

    That being said, because this part was intended to drop into the USB line it has a peripheral type port and a host type port to allow it to interface with the peripheral port of the end point device.  The downstream host port is side 2 of the device and it contains the proper pull downs and drive strength to provide host type communications.  The only thing holding it back from isolating a host is that full compliance to the USB spec requires that a host auto-detect the speed of any peripheral plugged into it.  The ADuM4160 was designed to operate at a single speed, set by hard wiring pins SPU and SPD.  So while it can be set and will communicate as a host isolator at either low or full speed, but it will be a fixed speed device however it is set, and so does not meet all of the requirements of the USB-IF standard.

    For many customers this is adequate for their job and they use it in this way.