1N4148W-E3-08 Protection Diode Burnt—What Causes Overstress and How to Prevent It?

Hi Experts,
I have been encountering diode protection burn-out, thats the diode D1 OPN:1N4148W-E3-08 got burnt and failed. Further x-ray investigation shows internal wires melted and burnt die which leads to suggestion of electrical over-stress and large surge current.
I attached the schematic enclosed.
Please advise what has went wrong and what additional circuit should be included to prevent such burnt-out from happening again.
Thanks
Wolde

It seems reasonable that you could burn up D1 due to the inrush current required to charge C2 when power is applied. Could you remove C2 or move it to the other side of R1 in parallel with C3 and C4?

You may need to provide more information about the input to determine if that would cause any problems.

I certainly would not have chosen a small signal diode in this application, a rectifier diode for power supply applications would have been more suitable,
cheers,
Richard

Hi, Wolde cosqrove,
Change c2,c4,zd1(increase the wattage rating of zd1 if possible to 2 watts )
finally change ic u1.also change d1 with a higher current rating go for IN4007.


Regards Sambath.

Hi,
It seems to be an automotive circuit.
You connected this circuit on Ignition line and in Automotive this is the most noisy power line in the vehicle. First thing is when you connect power supply circuit to battery/IGN line you have to consider Load dump and other ISO 7637-2 power supply line transients.
Possible Reasons to burn diode:
1) Surge current in case of load dump (better to use transient suppressor before diode or change D1 to FS1J the most famous diode in automotive.)
2) Inrush current due to C2.