Forum Discussion

SZack's avatar
SZack
Icon for Occasional Contributor rankOccasional Contributor
5 years ago

I have a customer who is looking to use the PLL in the MAX 10 to take a 25 MHz clock and generate a 100 MHz clock for a PCIe interface. Will the PLL in the MAX 10 meet the jitter requirements of PCIe Gen1?

2 Replies

    • SZack's avatar
      SZack
      Icon for Occasional Contributor rankOccasional Contributor

      Thanks Jw.

      I did come to the same conclusion after finding the jitterlabs site you mentioned. What puzzled me is that the jitter requirement of 6ps is so stringent that several PCIe clock generators I looked at do not meet this spec so I wasn't sure if this calculation was relevant. And when I looked at some documents describing the maximum phase noise and jitter requirements for PCIe Gen1 I saw numbers in the 85ps range. I also read that many PCIe applications use spread spectrum clocking and the MAX 10 PLL can definitely NOT provide that kind of clock output.

      Given my lack of certainty about exactly what the specs meant I recommended that the customer use a dedicated clock generator.

      Steve