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Original question:

DS80PCI402: DS80PCI402 - LPBK capability

DS80PCI402: DS80PCI402

Shlomi Yehezkia
Mastermind 6150 points
Part Number: DS80PCI402


Hi Team,

My customer are connecting 4 Lanes from DS80PCI402 device to Xilinx UltraScle FPGA SerDes.

The distance between the DS80PCI402 device to Xilinx UltraScle FPGA is about 10 inches

 

  1. What is the recommended  setting for RXDET pin and what are the considerations for this termination setting?
  2. What is the recommended setting for SD_TH pin and what are the considerations for this thresholds setting?

 

Do you know about some electrical limitation (ERRATA) of the device that they should know.

 

Can you approve that the Max Differential RX peak-to-peak is 1.2 V voltage (VID) and that there is no Limitation with this value.  

Thanks,

Shlomi

  • 0
    TI__Mastermind 43795 points

    Hi Shlomi,

    1. RXDET is recommended to Float for all PCIe applications.

    2. SD_TH is recommend to Float for all PCIe applications as well.

    The biggest "errata" type information is to locate the PCI402 close to the middle of the channel for best overall performance.

    A 1.2V input signal is not a problem for this device.

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Mastermind 6150 points

    Hi Lee,

     

    I want to understand if there is some correlation between RXDET setting and Equalization and De-Emphasis setting.

     

    According to my testing I found that in some cases there was correlation  between Equalization and De-Emphasis setting and RXDET setting to 50 Ohm that improved my test results.

     

    Is it reasonable?

     

    Thanks,

    Shlomi

  • 0 in reply to Shlomi Yehezkia
    TI__Mastermind 43795 points

    Hi Shlomi,

    In a normal system I would expect the RXDET (manual 50 Ohms or Automatic detection) to have zero influence over the equalization and de-emphasis settings.  If for some reason the devices are not properly detecting the termination and the input termination is not active, then the effective equalization level could sihft and need an adjustment to optimize the DS80PCI402 output signal.

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Mastermind 6150 points

    Hi Lee,

     

    Can you please explain in details what do you mean “If for some reason the devices are not properly detecting the termination and the input termination is not active”

     

    Thanks,

    Shlomi

  • 0 in reply to Shlomi Yehezkia
    TI__Mastermind 43795 points

    Shlomi,

    The only way that a manual 50 Ohm RXDET setting would impact the results would be the case where no active termination is connected to the DS80PCI402 output.  Without a termination on the output the automatic RXDET would turn-off the associated input termination on this channel.  Without the input termination connected and active, the device signal conditioning performance is poor.

    Regards,

    Lee