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DS80PCI800/402 EQ/DE setting

Patrick Chen
Mastermind 8875 points


Hello,

          The below are customer topology. Customer would like to confirm the EQ/DE level setting is correct for these lane trace. Has any problem or risk by below each lane? 

          The De-Emphasis setting has different VOD and DEM dB, do these De-Emphasis setting  with VOD output voltage have any issue for topology? Thank you.  

BR

Patrick

  • 0
    TI__Mastermind 43795 points

    Hi Patrick,

    The datasheet recommendations are based on a transmitter without any output equalization enabled.  For PCIe the transmit device will usually provide > 6 dB of output equalization to help compensate for the channel losses.

    I would start with much lower settings for all of the DS80PCIxxx devices and then work higher if needed.

    EQ: Level 1 (EQ[1:0] = 0,0)     //* This is the minimum level

    VOD/DEM: Level 4 (DEM[1:0] = 0,1)     //*  VOD = 1.0V and DEM = 0 dB

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Mastermind 8875 points
    Dear Lee,

    Do you mean EQ level 1 and VOD/DEM Level 4 are lower setting and start for these setting, right?

    For PCIe the transmit device will usually provide > 6 dB of output equalization, if datasheet recommendation for level 4 and 10", do we need consider and for lower setting example Level 3 or minimum Level 1, right? Thank you.

    BR
    Patrick
  • 0 in reply to Patrick Chen
    TI__Mastermind 43795 points

    Hi Patrick,

    Yes start with the lower DS80PCIxxx settings for EQ and DEM.

    Regards,

    Lee