I have the following circuit (see attached) where I am using a SI2302 MOSFET to switch an LED using a micro-controller (internal pull down.)
The problem I am seeing:
Upon switching between 3.3V (HIGH) and 0V (LOW) on the gate, the voltage measured on the drain pin switches between 0.6 and 0.7 volts, which makes the LED just slightly brighter/dimmer when switching, but it won't turn it on or off fully.
I would expect to see approximately 3.3 volts at the drain when the MCU output is low (MOSFET not conducting) and approximately 0 volts at the drain when the MCU output is high (MOSFET fully conducting).
I have read through some similar posts, but the issue there was that the MOSFET was probably broken or soldered the wrong way around. I have 6 of these circuits in parallel and all show the same issue.
UPDATE: Gate is driven by an STM32L051. Tried it with an external 10k pulldown resistor between gate and source. Same outcome. Tried it by disabling the STM32 and manually switching the Gate. Same outcome.
FINAL UPDATE: It was my bad, I soldered SI2303 instead of SI2302. Thank you all very much!