I am using the LT4356-1 for input protection against voltage and current faults.
My circuit has been working correctly for several weeks.
However, today I noticed the voltage downstream of the LT4356-1 was about 5V lower than the input supply voltage.
The supply voltage is 25V, and the voltage to the circuit varies from 20 - 22V.
On further investigation, I noticed that the voltage to the gate of the pass transistor is 25V, ie the same as the input voltage.
So, this causes the pass transistor to drop voltage.
The gate of the pass transistor is driven through 15 ohm, and the voltage is the same on both sides of the resistor, i.e. there is no drop across the resistor.
Is it possible that the LT4356 failed on startup this morning?
OR, is there something else I can check?
I verified that there is not a short between the input and the gate pin.
