Calulating gate capacitance other parameters of mosfet from datasheet

Discussion in 'General Electronics Chat' started by aamirali, Feb 6, 2012.

  1. aamirali

    Thread Starter Member

    Feb 2, 2012
    415
    1
    I have to calculate gate cap, now I got two methods, one is by looking at Vgs vs Qg graph & directly calculate Cgate = Qg/Vgs.
    Second is finding separately Cgs & cgD & then adding them.
    Problem is both gives two different results.

    Plz suggest me some links or application notes where I can calculate these parameters from mosfet datasheet.
     
  2. PaulEE

    Member

    Dec 23, 2011
    423
    32
    I would apply a signal between the gate and source/drain and look at the RC-like curve you get. You know the equation that describes the curve...

    Also, with your two methods, the current through the device causes the capacitance to vary. Does the spec sheet tell you under what conditions the graph was drawn?
     
  3. aamirali

    Thread Starter Member

    Feb 2, 2012
    415
    1
    there any many factors which effects these parameters. I have VGS=10V, & need a current of 1A.
    Is there any specific AN explaining how to calculate all the parameters by looking at mosfet datasheet
     
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