ADP150 LDO Input damage

Hi,
you should check that it is not C4 that is making the short circuit.
As the regulator has thermal protection, a probable reason for damage would be a overvoltage above 6,5V on the input.
What is your L1? Is it a ferrite bead?
Do you run long cables / wires between ISOW7841 and the regulator?
How hot gets the ADP150 with your maximum load (aproximately) ?
As IC has thermal protection, this is less likely the problem.
Is there another circuit connected to 3,3V output of ISOW7841?
What I don't understand:
Your ISOW7841 has 3,3V output voltage and your ADP150 also?

Hi Alex, 

I checked C4, it is not. 

It is hard to see the overvoltage in line, I performed long test but I did not observe overvoltage events.

L1 is just a standart ferrite bead. 

No, the wires and planes is really short between them. 

Total current which is supplied by ADP150 is around 16-17mA. Vın and Vout is around 3V3 so there is no much dissipation here. It is not get hot. 

There is no other circuit connected to 3.3V

Actually, ISOW7841 had an output of 5V but I changed it becase it was so close absolute maximum of ADP150. 

I also observed the startup, continuos waveforms and no I did not see overvoltages. 

Any other reasons for input short circuit ? 

Thanks.

Hi,
your case is totaly strange. There must be something overlooked.
Something one would never consider - like a (loose connection?) fault on the PCB
The only reasonable thing would be, is ESD, but with all the capaitors in place, it is almost impossible.
Or the ADP150 got overstressed and pre-damaged in the soldering process.
As you draw so less current out of ADP150 a load dump causing inductive overvoltage is also not possible.
Did you check the short circuit voltage of Vin of ADP150?
Was it only some mV?
Why did you use the ADP150 when ISOW7841 could provide 3.3V?
You know, that even a LDO must have some headroom to regulate?
So you must use 5V input. Maximum rating is 6.5V, so there should be enough margin.
As your circuit runs well for two months, unfortunately the fault is not replicable.
Probably the fault never happens again.
So, this is all I can say.