I have read some articles about USB ESD protection and followed the suggestion to add TVS Diode Array USB6B1 in my design. However, my design is still failed to pass the ESD test and I don't know where the problem is.

This is the testing procedure and result:

  1. Inject electrostatics on the product's metal surface, which is connected as the GND of the PCB.

    -- The USB transceiver reboot and USB connection break.

  2. Inject electrostatics on the USB port's shield.

    -- Same result as step1.

This is the circuit about USB protection. The power source of the board isn't from the USB, so the VBUS output pin is floating.

Can someone tell me where my problem is? Thank you~ enter image description here

  • \$\begingroup\$ Could you please share the PCB layout? \$\endgroup\$ – Rohat Kılıç Feb 12 at 5:15
  • \$\begingroup\$ The layout is the second thing. First thing is to draw the overall system configuration, whether this is a host or device, what the host is. The statement that "...metal surface, which is connected as the GND of the PCB" is the most suspicious thing - shield connection might need a special treatment depending on the system configuration. \$\endgroup\$ – Ale..chenski Feb 12 at 6:43
  • \$\begingroup\$ Maybe add some series resistors on the D+ and D- lines? \$\endgroup\$ – uglyoldbob Feb 12 at 14:04

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