Selecting the MOSFET

When selecting a MOSFET for either 3.3V or 5V applications there are three parameters to consider.

• Continuous drain Current (Id)
  • Amount of current the MOSFET can handle.
• Drain Source Voltage (Vds)
  • Voltage rating of the MOSFET (Do not exceed this value)
• Threshold Voltage (Vgs(th) )
  • Gate that will switch MOSFET on. (This value should be in the midrange of your microcontroller's power value. 1.7V(3.3V) or 2.4V (5V) min)

A load must always be on the drain side of the MOSFET due to the gate and source being hard connected inside of the MOSFET itself.