IC containing 4 MOSFETS with shared gate?

Discussion in 'General Electronics Chat' started by ALAS, Feb 8, 2015.

  1. ALAS

    Thread Starter New Member

    Sep 25, 2013
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    0
    Hi, I am trying to search for a device which I am pretty sure exists, but don't know what it would be called.
    It would be an IC containing 4 MOSFETs (N channel, enhancement) with a shared gate. I tried searching "quad MOSFET" on Mouser but didn't find what I was looking for.

    I am trying to use a single switch to switch on 4 independent (NOT parallel) branches of a circuit, without having to use a 4PST switch. I know I could do it with 4 MOSFETs each receiving the same gate voltage from a line controlled by the main switch but don't want to have to use 48 MOSFETs for this project.

    Also, please do let me know if there is a simpler or better solution that I have overlooked. My electronics knowledge is weirdly patchy so sometimes the solution I come up with for a problem is inelegant or needlessly complicated.

    Thanks!
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,046
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    What is the current and voltage of the switched branches?
     
  3. ALAS

    Thread Starter New Member

    Sep 25, 2013
    16
    0
    Both quite low. Line level audio (~1V DC peak to peak) and very low current (not sure how much but it's not a lot).
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,804
    1,105
    Google 'analog switch IC'. There are many out there.
     
  5. chuckey

    Well-Known Member

    Jun 4, 2007
    75
    10
    4066
    Frank
     
  6. crutschow

    Expert

    Mar 14, 2008
    13,046
    3,244
    If the signal voltage goes below ground you will have to take that into consideration when buying an analog switch.
    A CD4066, for example can't carry a signal voltage lower than the negative supply voltage.
    But some switches, such as these, can carry signals that go outside the supply rails.

    Alternately you can DC offset the signal at 1/2 the peak-peak AC level, using capacitor coupling, to insure that he signal never goes below 0V.
     
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