Hello
I want check I'm doing this right, and that I'm not being daft thinking the smaller SOT-23 mosfet will be suitable.
I am wanting to drive a few 12V 2.5W solenoids using an Arduino clone - Teensy 3.2, that runs 3v3 logic. The solenoid draws about 420mA at 12V when on.
Looking trough my box of stuff I have found two N-Mosfets that seem to do what I want:
SI2338: Max: 30V at 6A in a SOT-23 package
STD25NF: Max: 100V at 25A in a D-PAK package
Now I've always believed that to switch the transistor fully on, I should look for the Gate Threshold Voltage Vgs(th) and that this should be below that being used on the Gate - the 3.3V logic. For the SI2338 this is Min:1.2V, Max:2.5V and the STD25 Min:2V, Max:4V
I've made up the circuit on breadboard as in the badly drawn diagram, and switched between the transistors. Both appear to perform equally well, the solenoid clacks on and off as expected, nothing gets warm and on my cheap oscilloscope the signal looks square, I can't see any ramping.
Am I OK to use the SI2338? Or have I missed something?
Datasheets:
SI2338:
https://www.vishay.com/docs/67877/si2338ds.pdfSTD25NF:
http://www.farnell.com/datasheets/1689940.pdfThanks
Karl.