Hi,
customer to the 4kV surge test on the LM5069, found thath the LM5069 and MOSFET will be very easy demage. they add the TVS on the out pin, the clamp voltage is 75V. in the datasheet, the maximum voltage of VIN is 80V. the TVS part number is SMDJ85CA。
below is the schematic: add TVS on the between OUT pin and GND.
could you give some suggestions, thank you