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CDCDB800: Toe, Tod understanding and first clock waveform when enabling/disabling outputs

Taketo Sato
Genius 10485 points

Part Number: CDCDB800

Hello team,

I would like to confirm meaning of Toe and Tod spec of CDCDB800.

  1. Datasheet p.8, these are specified as maximum 10 CLKIN Periods.
    Does this mean in case CLKIN_P/CLKIN_N is 100MHz, it will take maximum 100ns(10ns x 10 periods) to start/stop output clocking from OE input?
  2. Do you have some waveform captures of CKx_P/CKx_N when enabling the output and when disabling the output?
    My customer would like to know actual(typical) time to start and stop, and would like to confirm first CKx_P/CKx_N clock waveform(pulse width and which CKx_P or CKx_N to start earlier and stop earlier).

Best regards,

  • +1
    TI__Genius 17025 points

    Hi Taketo,

    1. Correct. tOE is based on the clocking of CLKIN; a maximum of 10 cycles would be 100ns for f = 100MHz.

    2. Below is a waveform of OE and CLKout. The markers show the time it takes to disable the output when OE goes high, where yellow = OE and purple = CLKout. Please keep in mind this is a typical test and the actual amount of cycles can vary by design (max 10).

     

    Regards,

    Jennifer