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THAUS1's avatar
THAUS1
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4 years ago

MAX10 PLL with spread spectrum input

Hello,
I plan to use MAX10 FPGA PLLs, with Microchip a 25MHz DSC63xxB mems oscillator with spread spectrum feature.

I would like to know is MAX10 PLLs are able to lock on spreadspectrum modulation frequency about 33KHz. I understand that it depend of PLL Bandwidth setting.

The only information I found in UG-M10CLKPLL | 2018.06.15 is about bandwitdh Low/medium/High.
Is there some information about bandwitdh value with different setting?

Thanks

5 Replies

  • Farabi's avatar
    Farabi
    Icon for Regular Contributor rankRegular Contributor
    4 years ago

    Hi,

    I am Farabi who will support you on this request.

    Max10 devices can't detect if the input clock is spread spectrum clock or not. It will detect the spread spectrum input clock as jittery clock input. I attached Max10 datasheet and at page 27, there is spec mention about acceptable input clock jitter. Typically, Max10 required a clean input clock with maximum peak-to-peak clock jitter of 200ps.

    If you using 33khz spread spectrum input clock, I am afraid the jitter is too large and Max10 PLL can't detect the input clock signal you feed.

    regards,
    Farabi

    • THAUS1's avatar
      THAUS1
      Icon for New Contributor rankNew Contributor
      4 years ago

      Hello Farabi,
      I understand your answer.
      I've forget to precise that frequency deviation is about +-250ppm centered, and also frequency modulation about 33KHz.

      In my point of vue, 33KHz is more a wander than a jitter, because of low speed of triangle modulation at 33Khz.

      Am I wrong?
      Did you experience some customer such a DSC63XXB with MAX10 family?

      Thanks for your reply,

      best regards,

      Thierry

  • Farabi's avatar
    Farabi
    Icon for Regular Contributor rankRegular Contributor
    4 years ago

    Hi,

    We do not receive any response from you to the previous question/reply/answer that I have provided. This thread will be transitioned to community support. If you have a new question, feel free to open a new thread to get the support from Intel experts. Otherwise, the community users will continue to help you on this thread. Thank you.

    regards,

    Farabi