MOSFET failure & protection

[jalathar]

A P-channel MOSFET is currently used for switching the solenoid.

Case 1:
Is it possible for the MOSFET to fail?

Case 2:
If the MOSFET fails, will it become an open circuit or a short circuit?

Case 3:
If the MOSFET fails in short-circuit condition, how can the circuit be protected  

[Peter BENSCH]

Welcome @jalathar, to the community!

Your questions are questions about the fundamentals of electrical engineering and sound like exam questions from schools.

1. Yes, there are several reasons why the MOSFET fails
2. The impact of the failure can depend on several things: the cause of the failure, the design of the MOSFET, the board layout, etc.
3. For this specific case, only one fuse is necessary.

Is there a specific reason why you’re asking this in a forum for STMicroelectronics devices?

Regards
/Peter

[jalathar]

In case P Channel MOSFET get fail it become open circuit or short circuit (soruce and Drain)?

[Peter BENSCH]

A fixed probability for the two cases cannot be stated without specific data. A short circuit between D-S is usually more likely in the event of overload, while an open-circuit fault is more likely if e.g. connection wires, metallisation or mechanical structures fail. The exact cause depends greatly on what the overload looks like.

In short, there can be no general answer to your question.

Regards
/Peter

[jalathar]

My Use of MOSFET is switch the startrer motor solenoid 

If possible shortcircuit occur in source to drain ?

[AScha.3]

Yes.

[jalathar]

How to protect the short circuit