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TLK1221 minimum transition density

Greg Zschunke
Prodigy 40 points
Other Parts Discussed in Thread: TLK1221, TLK10031

I'd like to use the TLK1221 in non-sync mode for an application that does not use 8B/10B.  What is the minimum transition density requirement for the rx clock recovery?

  • 0
    TI__Genius 16150 points
    Hi Greg,

    The TLK1221 is intended for 8b/10b encoding/decoding, could you provide more information about your application to give you a better feedback.

    Best Regards,
    Luis Omar Morán Serna
    High Speed Interface
    SWAT Team
  • 0 in reply to Luis Omar Moran
    Prodigy 40 points
    We already use the TLK1221 in a design that uses 8b/10b. An application came up where we would like to use 64b/66b or some other type of encoding to reduce the 25% overhead hit or 8b/10b. To do that we are considering disabling the Synchronous Enable Function (SYNCEN low). Clock recovery circuits generally require a minimum number of transitions per unit time in order to correctly recover the clock.

    Two questions:
    1. Will disabling the sync function work in this case, so that the TLK1221 functions only as a deserializer?
    2. If so, what is the minimum number of transitions per unit time the clock recovery circuit needs to maintain alignment?

    Thanks,
    Greg
  • 0 in reply to Greg Zschunke
    TI__Genius 16150 points

    Hi Greg,

    For applications that do not require framed data the user can disable byte alignment by tying SYNCEN low. This device is compliant with 8b/10b encoding/decoding, hence, if you want to use 64b/66b I would suggest another option such as TLK10031.

    Regards,

    Luis

  • 0 in reply to Luis Omar Moran
    Prodigy 40 points

    Please have a support engineer call me regarding this issue.  Thanks!