Need help with A/D converter

Discussion in 'General Electronics Chat' started by bsj8377, Dec 31, 2006.

  1. bsj8377

    Thread Starter New Member

    Dec 31, 2006
    2
    0
    Hello all, I'm new to the forum and was wondering if anyone here may be able to help me with a question I have...I've been searching the internet for days now without any luck finding what I'm looking for...I need a stand alone A/D converter with a 3 or 4 bit output...also, it needs to accept up to 15 v on the input.

    Everything I've seen has been at least 8 bits, but that makes my logic circuit huge...and I don't need 8 bit resolution...

    Can anyone help me??? Thanks in advance!
    Brian
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    I don't think there are any conmmercial A to D's with less than 8 bits resolution. Just use one and ignore the lower 4 or 5 bits. If the 15 volts is a problem, use a voltage divider to put it in a range the A to D can handle.
     
  3. bsj8377

    Thread Starter New Member

    Dec 31, 2006
    2
    0
    I guess I could try that...just trying to keep it as simple as possible...and if they aren't offered commecially then that would explain why I couldn't find one online anywhere...thanks for the input, I think I'll try that and see what I can come up with...
     
  4. Distort10n

    Active Member

    Dec 25, 2006
    429
    1
    I have not seen a 3 or 4 bit ADC or DAC from any manufacturer. You will have to use an 8 bit converter and ignore the last 4 bits.
    When it comes to the 15V input you will also have difficulty as the industry is pushing toward single supply for portable/low power applications.
    A voltage divider on the input will be easy enough for a single ended, bipolar signal since it sounds like you do not need the greatest precision in the world. Otherwise, use an op-amp attenuator.
     
  5. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
  6. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    He's looking for analog-to-digital.
     
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