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Mono Audio DAC for ~20Mhz Microcontroller Synthesizer

  1. Jan 14, 2012 #1
    I have just joined EE senior design class. We have decided on making a synthesizer box with bunches of controls available to us. Ultimately, we would like to be able to output sound analog straight to headphones or external speakers through a 3.5 mm jack (standard headphones plug).

    I was looking through parts however, and can't seem to find a suitable audio DAC chip. The microcontroller we are using will be 16 bit architecture due to the error in 8bit calculations for audio. Would it be impossible to get a dac that can convert from digital to analog 1) mono channel or stereo 2) at a data rate of 48Ksamples/second.

    Part of the problem might be that I'm not totally sure what I'm looking for. I initially assumed i was looking for something that looked like this in 16-bit form...


    ....in which each input pin would be a digital output pin of the Microcontroller. But everything with quality output I find either seems to be using advanced communication techniques such as I2C such as the max5541 or SPDIF as seen in this demo...


    ...but this requires much higher communication rates in the Ghz range. Can a microcontroller that's doing a whole bunch of other crap also output a 6Ghz Serial signal. Why is this crap so complex? There is also this IC that keeps showing up in my searches called the PCM2902 that I can't make heads or tails of. It looks like filter for analog signals but implemented digitally; it's called a DAC but for some reason it has an ADC... what's going on here?

    It must be easier than I'm making this, but as per usual, I'm missing something basic when it comes to applications of theoretical EE courses.
  2. jcsd
  3. Jan 15, 2012 #2
    I found 80+ devices in 1 minute. Here's the first one:

    http://search.digikey.com/us/en/products/LTC1657CGN%23PBF/LTC1657CGN%23PBF-ND/963782 [Broken]

    I suggest that the weak link in your course is finding components. This is something every EE should have a handle on.
    Last edited by a moderator: May 5, 2017
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