Dear Sir 

We have developed 20 Watts LED driver circuit using LNK417EG .

The output voltage is 42 V and current is 420mA.

For output forward rectification we are using MBR20200CTG schotkey diode.

During higher input voltage range 270 Volts the MBR20200CTG schotkey diode is getting break down and its is not working .

At higher voltage range only the schotkey diode is breaking down and not working and it is getting shorted  .

Please tell me what is reason . Whether we have to use snubber parellel to the schotkey .

But also we have tryed out with MOSPEC S20C200 shocttkey diode , it is working very nicely and all input voltage ranges.

Please guide me to rectify this above problem.