I'm trying to replace a normally open switch with a low-side switch mosfet. The drain of the mosfet is connected to an input pin of a non-modifiable 3.3V MCU.
Prior to my changes to the setup the HIGH side of the switch measured around 3.3V since it's a LOW = TRUE logic input.
After I added a 5v long-period square wave (~5V high, 0.070V low) to the gate of the mosfet the voltage changed drastically at the drain side of the mosfet.
MOSFET ON - V_ds = 0V with V_gs = 5V as desired.
MOSFET OFF- V_ds = 1.7V with V_gs = 0.070V - HALF of what it should be with the mosfet switch open.
Anyone have any insight as to why this would be? From what I can tell I'm utilizing the 2N7000 well within spec.