Our customer carried out ESD test as attached but ADuM3160 seems not to withstand over +/-2kV.
When over +/-2kV ESD is applied, USB communication fails. Customer tried to test several samples and all of
them could not withstand over +/-2kV. (+/-4kV is must spec for the customer)
Customer also tried to remove ADuM3160, connect DD- and UD-, DD+ and UD+, GND1 and GND2 and short L508,
and then tested same thing, USB communication did not fail until +/-7kV.
Customer's schematic and PCB layout around ADuM3160 have any problem?