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can we use higher bit ADC for lower volt full resolution

Discussion in 'Microcontrollers, Programming and IoT' started by strameshkumar, Apr 2, 2012.

  1. strameshkumar

    strameshkumar

    25
    0
    Feb 23, 2012
    can we use higher bit, higher volttage i/p ADC for lower volt with full resolution?

    16bit +/-10v analog input SAR type ADC:
    In this ADC can we use 16 bit Resolution for 3V input level?
     
  2. timothy48342

    timothy48342

    218
    0
    Nov 28, 2011
    Someone might know exactly what your talking about, but...
    Can you give some context?
    Also, what is:
    "higher bit"
    "i/p"
    "ADC"
    "SAR"
    ?

    -tim
     
  3. strameshkumar

    strameshkumar

    25
    0
    Feb 23, 2012
    hi Timothy,
    The meaning s are i/p is input, ADC means Analog to Digital converter, SAR means successive approximation Register type.
    i am using 16bit +/-10V ADC , Is this possible to use 3V analog input for getting 16 bit resolution with that same ADC,
     
  4. timothy48342

    timothy48342

    218
    0
    Nov 28, 2011
    I should not have posted. Sorry. I got nothin'.
    I'm out. *brushes off hands*
    For the benefit of anyone else that comes along...

    What is the bands names and model numbers of the devices your using?
    Which "ADC" do you have?
    What is your end goal?
    --tim
     
  5. strameshkumar

    strameshkumar

    25
    0
    Feb 23, 2012
    model:AD9766A,
    my goal is to get full scale accuracy for 3V input
     
  6. timothy48342

    timothy48342

    218
    0
    Nov 28, 2011
    I am way better at hunting things down on the internet than actually understanding the things I find. However in this case I cannot even find anything about the "AD9766A."
    I did find a data sheet on the AD976/AD976A.
    Link:http://www.farnell.com/datasheets/188484.pdf
    Is that your chip? Could it be the 976, rather than the 9766.

    Apparently it takes an analog input dignal that spans -10V to +10V and produces some sort of digital output? (I was wondering the type of input signal, like maybe audio or something else, and I think the answer to that might be "any analog input".)

    I started to look through the data sheet that I found, and it is beyond my skills. Hopefully someone else knows more.

    Definately check this datasheet and make sure I didn't get the wrong one. This is the 976, and you said 9766.

    Good luck to ya,
    --tim

    Edit: At least I understand the question now. You want to feed a 3V analog signal to a device that is expecting a signal that can go from -10V to +10V and you want to know about the digital resolution of your output.:endEdit
     
    Last edited: Apr 2, 2012
  7. gorgon

    gorgon

    603
    24
    Jun 6, 2011
    You have two ways to do this.
    You can amplify the 3V to fit into the 10V range for 15bit or 20V range(if you talk about a 0-3V input range) for a 16bit range. To do the last you'll need to do some tricks with offset and 0V level, if your input amp is bipolar.

    Or, you can reduce the ADCs reference voltage to fit a full range of 0-3V.

    If you talk about the AD976A, the only way to do it is to amplify the 3V to fit the input range of +/-10V, since the reference voltage is built into the chip. You will need a low impedance source amlifier to the input due to the 12k input impedance of the ADC.

    TOK ;)
     
    Last edited: Apr 2, 2012
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