yeah, we have design this pin ESD protection, but when silicon comeback, the protection is failed, we used 19 series HV diode conect this pin to GND, the test voltage is -8v, but test data show there are leackage between this -8 output pin to GND.
Added after 4 minutes:
There are many problem about our ESD protection design, but why they not work, we have not found the reasons, more we need to do for our chip, it is so hard to us.