Connect with us

Looking for a cheap >800ksps 16-bit D/A

Discussion in 'Electronic Design' started by SioL, Sep 5, 2006.

  1. SioL

    SioL Guest

    Hi there,

    I'm looking for a cheap D/A, needs to do at least 800ksps at 16 bits.
    More speed or better accuracy would be welcome, but I'm not prepared
    to pay an arm and a leg for that bonus.

    From what I see so far prices go crazy at such speeds and resolution.

    SioL
     
  2. Guest

    Depends what you mean by crazy

    http://focus.ti.com/lit/ds/symlink/ads8371.pdf

    is claimed to be $12 for 1k quantities, offering 750k sample/sec. for
    $12.66 you can go up to 1.25M samples/sec with the

    http://focus.ti.com/lit/ds/symlink/ads8401.pdf

    The Analog Devices part

    http://www.analog.com/UploadedFiles/Data_Sheets/3409832066141394038AD7725_a.pdf

    is $20 in 100-up qunatities, but it is sigma-delta.

    http://www.analog.com/UploadedFiles/Data_Sheets/297966481931038630530425AD7653_a.pdf

    is SAR, but only costs $12.72 100-up.
     
  3. SioL

    SioL Guest

  4. Guest

    If you want cheap then you dont need 16 bits. It's very unlikely you
    need 16 bits anyway and even more unlikely you'll get it even if you
    were prepared to pay. 12 bits is the realistic limit for low cost
    options.
     
  5. Some of the audio ones come close to your stated requirements.


    Best regards,
    Spehro Pefhany
     
  6. John  Larkin

    John Larkin Guest

    TI's DAC8541 is about $3 in quantity. Ole reliable PCM56 is cheap,
    bipolar, internal ref, available in DIP, and is actually pretty good
    at DC.

    Both serial, of course.

    John
     
  7. Guest

  8. Joerg

    Joerg Guest

    Hello Spehro,
    SioL might consider using these in staggered fashion to achieve the
    required sample rate. I did this a lot with ADCs.
     
  9. SioL

    SioL Guest

    DAC8541 is way too slow, at 10uS settling time. PCM56 is much better at 1.5uS,
    but still too slow for 800ksps.
    That's what I'm looking for :)

    SioL
     
  10. SioL

    SioL Guest

    Hmm, using another D/A to provide ref. voltage for the first D/A?

    SioL
     
  11. SioL

    SioL Guest

    It happens :)
    This one looks good. I thought there might be something cheaper out there.
    I guess I'll have to adjust my target price a bit higher.

    Help appreciated!

    SioL
     
  12. Joerg

    Joerg Guest

    Hello SioL,
    That won't likely become accurate enough. I was thinking of using
    several slower audio DACs and then having them feed an output node in a
    round robin fashion through a "chopper". I usually had to do this the
    other way around, using ADCs that were too slow for the application and
    then ganging several. This is much more difficult than DAC ganging
    because I had to auto-align gain, offset and clock phase. The latter is
    the tough one but in your DAC application you might not have to worry
    much about it.
     
  13. SioL

    SioL Guest

    Hey, thanks, that's an interesting idea indeed, could save ~4-5 US$
    I'll see how I fare with PCB real estate.

    SioL
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-