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carpenter
carpenter
Visitor II
March 10, 2016
Question

STM32F373 DAC noise?

  • March 10, 2016
  • 3 replies
  • 905 views
Posted on March 11, 2016 at 00:21

Where do I find information about noise of DAC in STM32F373, for example

Output Noise Spectral Density ?

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    3 replies

    Amel NASRI
    Amel NASRI
    ST Technical Moderator
    March 14, 2016
    Posted on March 14, 2016 at 15:20

    Hi ismail.carpenter,

    Your request is not so obvious, could you please provide some more details?

    -Mayla-

    To give better visibility on the answered topics, please click on "Best Answer" on the reply which solved your issue or answered your question.
    jogerh
    jogerh
    Associate III
    March 14, 2016
    Posted on March 14, 2016 at 21:49

    Hello,

    the DAC noise depends on the sampling rate and the bit resolution you’ve chosen. If you have 4096 steps to sample 3 V one would expect to get roughly 1 mV per step (~70 dB SNR) however depending on the setup you're using  (e.g a disco board) it might get worse. I’ve seen some 20 mV PP noise with repetitive 100 mV peaks inside on the scope screen while the STM32F37x DAC was outputting a constant voltage.  However as mentioned this depends on the current setting (e.g. also what kind of periphery is additionally activated). Sometimes it’s useful to consider a reconstruction filter.  Depending whether the application is a highend one would also consider to use a synthesizer ic instead to reach higher performance. 

    AvaTar
    AvaTar
    Senior III
    March 15, 2016
    Posted on March 15, 2016 at 06:58

    > Depending whether the application is a highend one would also consider to use a synthesizer ic instead to reach higher performance.

     

    I'd second this. Having analog units (DAC, ADC) on the same silicon as digital circuitry switching in the high-MHz-range is incompatible with the idea of ''high end''.

    ADCs and DACs on a microcontroller are always a compromise and a convenience. If you need maximal quality, use external units.

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