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Choose the right Mosfet

Discussion in 'General Electronics Discussion' started by aaronik19, Sep 4, 2017.

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  1. aaronik19


    Sep 4, 2017
    Dear Friends,

    I would like to choose a N-Channel Mosfet which needs to be triggered by 5V signal to switch on, and 0V to turn off. The amount of current needed is about 2A from Source to drain (to drive the load). Am I right to say that on datasheets I need to look for the VGS to be able to drive from 5V microcontroller?

  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    Jan 21, 2010
    Look for a MOSFET described as "logic level"

    You probably should be looking for something which is rated for a continuous Ids of 4A or more.
  3. BobK


    Jan 5, 2010
    And don't be fooled by the gate threshold voltage. That voltage is what it takes for the MOSFET to pass 250μA, it will not turn the MOSFET on for a 2A load. The threshold voltage is more of an indicator of what voltage will turn the MOSFET off completely.

  4. Awesome Academy

    Awesome Academy

    Sep 6, 2017
    There are two relevant datasheet parameters here. The first you are looking for is Vgs(th). It needs to be significantly below 5V. But even better than this, look for information on Rds(on) at different values of Vgs. If you get for example Rds(on) of 50mR at Vgs=4.5V then heat generated in the FET would be a very reasonable 2*2*0.05=0.2W.
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