MAX333A(analog and digital parts)

Discussion in 'General Electronics Chat' started by Crowbar, Dec 19, 2006.

  1. Crowbar

    Thread Starter Active Member

    Dec 19, 2006
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    Hi. I have a question about MAX333A analog switch: It will be used to switch on-off HPF filters. My circuit have separated analog and digital grounds, connected in a single point(star)- max333a have only one GND pin(no separated agnd dgdg)- how this GND must be connected to analog and digital grounds of my circuit(should i connect only dgnd to MAX333A GND or agnd must be connected also)?

    Regards, Konstantin.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    282
    Hi,

    Looking over the spec sheet, the ground pin is used as a reference for the logic signal, so connect to the digital ground.
     
  3. Crowbar

    Thread Starter Active Member

    Dec 19, 2006
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    Howhever, this anlog switch is using transistors of course- as i remember the simple transistor switch has common emitter which is connected to gnd; to be honest- I am dissapointed looking on MAX333(sorry, where at pdf Have you seen that gnd is used as a digital reference?)

    Best Regards.
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    The analog switch uses FET's as switching elements. I've used analog switches before - the logic signal needs the ground. The limits of the switch's signal capability are set by the V+ and V- terminals.
     
  5. Crowbar

    Thread Starter Active Member

    Dec 19, 2006
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    Ok, thanks for your expirience, cause i've never used analog switches before.
     
  6. Crowbar

    Thread Starter Active Member

    Dec 19, 2006
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    How can I calculate voltage noise which is given by MAX333?
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    Look over the spec sheet for the device. The information will be there.
     
  8. Crowbar

    Thread Starter Active Member

    Dec 19, 2006
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    There we have leakage current and on resistance only wich affects noise, i suppose, but no directly noise specs..
     
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