Failure of AD 8kv ESD test

[zhang.sandy]

Hi  Support Team

Our product have a CD 4kv and AD 8kv ESD test, but the samples reset on AD 8kv close to the USB, the reset register show it is nRESET PIN reset.

add an ESD diode to this pin, no any improving. removed C13 and R7, the ESD is improved, but still have chance to be failed. 

Is only nRESET PIN can trigger thise reset? Any suggest from your side, we can offer SCH and PCB file if you need. 

[ketiljo]

Do you need the reset line? If not, you can omit it.

The device itself isn't designed to withstand 8 kV so you need additional ESD protection on the USB lines. 

Also, is reset a problem for the qualification testing?

[zhang.sandy]

Yes, i need reset line to do HW reset, and our product certification need ESD pass at CD 4KV and AD 8kv. below is the USB circuitry, do you have any additional ESD protection to reccomend? thanks

[ketiljo]

You should have a protection diode on the VBUS line, very close to the USB connector. Make sure the diode is properly grounded. Tracing ESD issues can be tricky so you have to experiment with diodes at different places.