• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 33 subscribers
  • Views 300 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DS80PCI102: RATE pin connection and de-emphasis level

user6004480
Intellectual 660 points
Part Number: DS80PCI102


De we have to set RATE pin = Float to activate DEMA/B pin in PIN MODE ?

We expect only GEN2, So RATE pin is tied with 1k ohm register to GND in Our board current design.
and we also expect DEM = 0dB, So DEMA/B pins are tied with 1k ohm register to GND.

However
Refer to Datasheet(SNLS344G)
described "The de-emphasis levels are available in GEN1, GEN2, and GEN 3 modes when RATE = Float" in page 14.
We wonder DEM = 0dB or not, when de-emphasis levels are not available.

  • 0
    TI__Mastermind 43795 points

    Hi,

    Setting RATE = 1K to GND will keep the datapath in a GEN1/GEN2 mode of operation.  This mode uses a limiting output driver stage.  All de-emphasis settings are available in the mode.

    Setting DEM = 0 dB will result in no output de-emphasis on the signal.  For longer output channels in GEN1/GEN2 systems either -3.5dB or -6dB settings can be used effectively to help compensate for some of the channel attenuation.

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Intellectual 660 points

    Hi Lee,

    Thank you for  kind clarification !

    If signal quality gets better or we change board design,
    We will try changing de-emphasis levels.