Hi,
The circuit in the datasheet surely works.
But YOUR circuit fails.
Therefore - if you need help - give us YOUR schematic and YOUR PCB layout. And all technical informations...
2) what can I do to prevent next fault (now, with present layout and later, at the next layout)?
Follow the design rules and the specifications given in the datasheet. That´s all.
1) What can be the reason? ESD? or else?
If you look into the datasheet, then yo will find a lot of specifications. All with values and units.
But in your post there is not a single value and not a single unit.
--> it is impossible for us to decide what can be the problem.
So give us YOUR data:
* input voltage (best: min, max, avg)
* output voltage (desired, measured)
* output current (average, peak)
* what´s the load? Switched? HF?
* are inductors involved?
* what capacitors do you use?
* temperature after a while of operation.
Klaus