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Q&A MOSFET not turning completely off

Hello everyone, I have a simple circuit in which I control some LEDs via an MCU and DMG2302UK ( N-channel MOSFET ) The EN pin is connected to an MCU gpio pin that works at 3.3V. The circuit wo...

1 answer  ·  posted 2y ago by AhmedMobarez‭  ·  last activity 2y ago by Olin Lathrop‭

Question MOSFET
#1: Initial revision by user avatar AhmedMobarez‭ · 2021-10-18T17:01:23Z (over 2 years ago)
MOSFET not turning completely off
Hello everyone, 

I have a simple circuit in which I control some LEDs via an MCU and DMG2302UK ( N-channel MOSFET )

![Circuit schematic](https://electrical.codidact.com/uploads/8LFLT8WicZYGyJH5QvxRGTVy)

The EN pin is connected to an MCU gpio pin that works at 3.3V.

The circuit worked perfectly for some time, and suddenly the LED were always-on (very dim), there was some sort of leakage current, changing the resistor and the capacitor didn't help, it only worked again when the MOSFET was changed with a new one.

Note that the MOSFET was switching successfully as I can see the LEDs turning brighter when switched ON, but it just doesn't turn completely OFF

I imagine that something might have damaged the MOSFET but not sure what, the main thing I am thinking about is not connecting a resistor between the gate and the EN pin which might have damaged the MOSFET with time as per this [page](https://www.homemade-circuits.com/mosfet-protection-basics-explained-is/)

What do you think might have damaged the MOSFET ? and how to enhance this circuit ?

Thank you