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Analog switch input voltages...

Discussion in 'Datasheets, Manuals and Component Identification' started by katanoma, Dec 10, 2011.

  1. katanoma

    katanoma

    11
    0
    Dec 10, 2011
    Dear All,
    I have an analog switch MAX4685 to be supplied by 2.7V and used to convert signal of (3*10^-3)V, the datasheet mention that VIL=+1.4V and VIL=0.5V, so can i use this switch to convert the (3*10^-3)V ??
    and can i use the traditional NE555 as a timer control signal for controlling the switch??

    attached are parts of the datasheet...
    Thanks for your help and hoping to receive your response asap.

     

    Attached Files:

  2. Harald Kapp

    Harald Kapp Moderator Moderator

    9,398
    1,920
    Nov 17, 2011
    Hi,
    the MAX4685 will not convert your signal to anything, it will just switch it through or not, depending on the control signal.
    Operating the MAX4685 from 2.7 V is o.k. (the datasheet specifies 1.8 V ... 5.5 V).
    The switch caan easily handle 3mV.
    Control via a NE555 is possible as long as the control signal does not exceed the operating voltage (0...2.7 V) of the MAX4685. Since you work with 2.7 V, the standard NE555 will not work well. Better use a CMOS version like e.g. ICM7555, TLC555 or similar.

    Regards,
    Harald
     
  3. katanoma

    katanoma

    11
    0
    Dec 10, 2011
    Hi Harald,
    sorry for using "convert", it is switching :)
    I am planning to use the NE555 to generate the control signal of 8 MAX485 switches. So i think we may supply these switches with 5V and hence the 4.5V of the NE555 will work properly, but at this point,, i am afraid of the voltage drop of the NE555 due to the load current
    .

    Best Regards
     
  4. Harald Kapp

    Harald Kapp Moderator Moderator

    9,398
    1,920
    Nov 17, 2011
    Which load current?
    The datasheet states:
    IN_ Input Leakage Current IIN_ VIN_ = 0 or V+ E -1 ... 1 μA
    So with 8 switches you have a load of at most 8µA (or 16µA if you mean 8 ICs with 2 switches each). 8µA is nothing an NE555 cannot drive.


    Regards,
    Harald
     
  5. katanoma

    katanoma

    11
    0
    Dec 10, 2011
    Ok, so i can use the attached NE555 circuit made by TIINA-TI, the steady state is attached also,, but in fact i couldn't simulate it using TINA-TI,,, only the steady state...

    Many thanks for your efforts,, they were of great benefit for me.....


    Best Regards
     

    Attached Files:

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