I'm designing a controller for LED module operating at 24 volts. The module will use about an amp of current and is controlled by Atmega32.
After research I found that N-channel MOSFET used as low side switch is the best approach. I also learned that two resistors are recommended on the gate. One is pull down resistor and the other is in series with the gate to reduce some oscillation.
This was clear but the selection of the FET was not. My requirements were at least one amp of drain-source current, easy to solder SMD-package and logic level. There were hundreds of parts matching this criteria on Digikey and I settled on
DMN6140LQ for now.
The circuit I designed is in the attached picture. The label Y is connected to AVR output and the connector on the top is connected to the cathode the LED.
My questions are the following?
1. Is my design sane or is there some error?
2. Are there some rules to select components like the FET in this example? There are so many nearly identical options. Is the best way to just select the cheapest?