I am trying to convert a 3.3V logic signal to 5V logic signal. I am using a p-channel MOSFET and I can not get it to send the full 5V signal through. Below is the circuit I am using.
Electrical – 3.3V to 5V logic converter using p-channel mosfet
3.3v5vconvertersignal
Best Answer
Use an N-channel MOSFET, or swap the 100k resistor and the P-channel MOSFET.
Also, it'll work a bit better with a lower value resistor. Say, 10k. And both circuits will invert your logic. If you cannot deal with that, then you need a few more components (another MOSFET, for instance).
See the below diagram for two ways that work.
simulate this circuit – Schematic created using CircuitLab
The MOSFETs in the schematic are merely symbolic, the part numbers may or may not be appropriate.
Because of your 3.3V input, you must choose a MOSFET with an appropriate low turn on voltage. That is, \$V_{gs(th)}\$ must be sufficiently below 3.3V, otherwise your MOSFET will not turn on or be barely on.