ADuM3160 with USB2.0 & 3.0

Document created by analog-archivist Employee on Feb 23, 2016
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I have a device in production where I use the ADUM3160 to isolate an USB HID
I never face any problem till now.

In some PC with a USB3.0 (RENESAS USB 3.0 HOST CONTROLLER) the peripheral is
not recognized (Unknown device in the Device Manager)
In the same pc if I use a USB 2.0 port everything is ok. I made a test removing
the ADUM3160 from the board and the PC recognize the peripheral in the USB3.0
port. I attached the schematic.


We have tried the ADuM3160 in USB3.0 computer ports and did not have any
difficulties. The super high speed part of USB3.0 is a separate data path that
does not need to be connected for the USB2.0 part to work.

The only thing I might suggest is that the PIN input may be applying the pull
up and trying to enumerate before the optocoupler charges up and tells the
processor that it is OK to enumerate. As an experiment, try holding PIN low
until the cable is plugged in then set it high and see if enumeration happens.
If that works, you could use the power good signal (voltage divided down) to
run the PIN and make enumeration sync up properly. Alternatively short R125 to
Vdd and see if that fixes the problem.

After that we would need to see the scope traces of D+/D- as the cable is
plugged in. Let me know how it worked out.
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