We using TI LM4950 in our production and we fail average 1 a month in production area due to the output cable shorted to ground this case both output short to ground at the same time and the LM4950 Blew.
Reviewing the TI spec sheet on LM4950 says short circuit protection; The LM4950 features an internal thermal shutdown protection mechanism along with short circuit protection.
I did some experiments:
Ground one side of the output of LM4950 OK
Ground one side of the output and ground the other to ground of LM4950 OK
Ground both sides of the LM4950 at the same time and tie ground the LM4950 Blew
It looks like the LM4950 does not have a good output protection to ground
I try PTC at the output to protect the LM4950, the problem is the nature of PTC is response to slow and will not have enough time to protect the LM4950.
Any advice or guidance to protect the LM4950 would be greatly appreciated.