I have an Analog 12V RGB LED strip (which only requires 1-2 amps at most) that I want to control using an Arduino Uno. I looked into how I could go about doing this and saw that i could use several Logic Level MOSFETs to control the RGB pins on the LED strip.
I intend for the Arduino to send PWM signals to the gate (with a 10k pulldown) to control the brightness of the LEDs.
I can easily get hold of some STP55NF06L N-Channel MOSFETs which I initially thought should be able to do the job since the Gate Threshold Voltage is 1.7 volts. However I read too much off of the internet about what MOSFETs can be used with Arduinos and now I am unsure if they will work. One website told me one thing while someone else told me another. There was a lack of a clear cut definition.
Will these MOSFETs work with the 4-5V signal from an Arduino? If not, can you suggest any alternatives?
Also, if anyone can explain what should I be looking at in the datasheet to help me figure out if they are logic level, I'd be extremely thankful.
Best Answer
Forget Vt. What you should look at is Rds(on) at 5V drive which is 0.02 ohm maximum (will increase with heating, but not more than 50%). At 2A the heating will be no more than 120mW so you won't be needing a heat sink for static switching (you can verify my latter claim from the thermal characteristics). The 0.02 ohm is a 100% tested guarantee by the manufacturer, not a "typical" characteristic, which may or may not be accurate for any given device.
If your PWM frequency is high, there may be significant heating from the slow switching due to not having a high current gate driver but at a few hundred Hz it will almost surely be fine.