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DS250DF410: Do PRBS and PRBS functions require additional clock input?

Part Number: DS250DF410

I have two questions to consult, please help confirm

1. What is the rate range supported by DS250DF410 to send PRBS and PRBS check?

2. Do these two functions require additional clock input?

    1. The DS250DF410 can output PRBS pattern while operating in PRBS generator mode for the full ranges of data rates specified in the datasheet
    • Full-rate - 20.2752Gbps to 25.8 Gbps
    • Half-rate - 10.1376Gbps to 12.9 Gbps
    • Quarter-rate - 5.0688Gbps to 6.45 Gbps
    • For a retimer channel to generate PRBS data a reference input signal is needed on its high-speed inputs for its CDR to lock to. This reference input signal may be a 1010 clock pattern at a sub-rate frequency multiple of the main data rate

    Cordially,

    Rodrigo Natal

    HSSC Applications Engineer

  • According to the reply,
    the condition for the DS250DF410 generate PRBS Pattern, is that there is a reference clock at the high speed input?
    What about the Pattern Checker,also need a reference clock input at the high speed?

  • Let me clarify further.

    The requirement for PRBS generation is that there be some input data present that the retimer CDR can achieve CDR lock with. It can be either:

    • Standard encoded (e.g. 8B/10B, 64B/66B) data at full rate, half rate, or quarter rate within the retimer datasheet limits
    • 1010 clock pattern at sub-rate of divider as low as 32 (e.g. 402.832031MHz square wave if CDR is programmed for 25.78125gbps rate)

    The PRBS checker may be enabled even if there is no input data present. obviously if there is no input data the error count will immediately max out and retimer will indicate no pattern detected.

    Cordially,

    Rodrigo Natal

    HSSC Applications Engineer

  • What about the Pattern Checker,also need a reference clock input at the high speed?

    Could you please answer this question? Thank you!

  • The TI retimer Rx channel simply needs input PRBS data to be able to perform its PRBS checker function. Note that the TI retimer uses a simple 25MHz input calibration clock.

    Cordially,

    Rodrigo Natal

    HSSC Applications Engineer