mosfet on-resistance

Discussion in 'General Electronics Chat' started by sheateo, Jan 29, 2012.

  1. sheateo

    Thread Starter New Member

    Jan 17, 2012
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    How does mosfet on-resistance affect the design of a circuits like a analog switch?
     
  2. nigelwright7557

    Senior Member

    May 10, 2008
    487
    71
    It should be irellevant compared to other resistances in the audio circuit.
     
  3. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    It limits the amount of current the FET switch can pass since the power dissipation is I(squared) X RON. On resistance is the key money spec for switching FETs.
     
  4. crutschow

    Expert

    Mar 14, 2008
    12,974
    3,220
    To minimize error in the signal transmission through the switch, the load resistance on the switch output should be much greater then the switch resistance. Otherwise the switch resistance in series with the load resistance will act as a voltage divider and reduce the signal voltage. Since the switch resistance typically varies some with the signal voltage it could also induce signal distortion.
     
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