Reason for Tracking Skew not Specified in CY7B994V

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    Question: Can I get the tracking skew of CY7B994V?



    Please note that we usually do not offer tracking skew or tracking jitter on most of our RoboClock data sheets. However, our RoboClock datasheets have a Total Timing Budget (TTB) specification in them. The TTB for our CY7B994V-2 device is 500 ps maximum and for our CY7B994V-5 device is 700 ps maximum. TTB tries to specify the worst-case timing you will ever see from the chip. Please find attached below a slide showing that TTB includes skew plus all necessary jitter to give the total maximum uncertainty you should ever see.

    For PLL devices, we usually specify the cycle-to-cycle jitter only as cycle-to-cycle jitter is important for the system using PLLs in serials. If the cycle-to-cycle jitter is too high, it may cause down stream PLL lose lock or high tracking skew.

    It should be noted that PLLs are normally capable of tracking long-term jitter. PLLs, by design, are incapable of tracking cycle-to-cycle jitter, because the PLL response time is typically slow. When the modulation occurs at a rate and level that is too difficult for a PLL to track, the PLL may give a "best-effort" tracking which we refer to as tracking skew.