Choosing the right DAC

Discussion in 'General Electronics Chat' started by Peytonator, Dec 10, 2013.

  1. Peytonator

    Thread Starter Active Member

    Jun 30, 2008
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    3
    Hello,

    I am wanting to produce a sinc function with a bandwidth of around 100-300kHz. I will generate the sinc function using a DSP and then convert it to an AC signal using a DAC.

    I'm trying to find the right DAC to do the job, but just can't seem to make sense of the options from suppliers like Analogue Devices.

    http://www.analog.com/en/digital-to-analog-converters/high-speed-da-converters/products/index.html

    I need an output frequency range of around 300kHz, but all the DACs are specified in terms of "update rate". What is the lowest update rate that will work with my output frequency range?

    How do I choose the right DAC?

    Many thanks.
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    For an output signal of 300kHz you need to update the DAC about ten times that rate.
    Hence you need to send parallel data at about 3Msps.
    You want a DAC with a settling time of 300ns or less.
     
    Peytonator likes this.
  3. Peytonator

    Thread Starter Active Member

    Jun 30, 2008
    105
    3
    Thank you, MrChips. What about if I send the data serially? How fast do I need to send it then?
     
  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    How many bits, including overhead bits?
     
  5. MrChips

    Moderator

    Oct 2, 2009
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    If you are sending 8-bit data then the serial clock frequency will have to be at least 8-times your sample rate, i.e. 24MHz.

    It will be hard to find a serial DAC with such high clock speeds.
    You will have more success finding an 8-bit parallel DAC with a settling time under 1μs.
     
  6. Peytonator

    Thread Starter Active Member

    Jun 30, 2008
    105
    3
  7. crutschow

    Expert

    Mar 14, 2008
    13,056
    3,245
    For that kind of speed you should stick with a parallel connection.
     
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