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SN75LVPE5412: EQ setting

Jeff YANG
Mastermind 7395 points
Part Number: SN75LVPE5412
Other Parts Discussed in Thread: DS320PR810,

Tool/software:

Hi,

Could you please advise on the current project, which plans to use TI_SN75LVPE5412RUAR and TI_SN75LVPE5412RUAR.

The trace lengths are as indicated in red below, and the board material is ultra-low-loss. Which EQ setting level should be used?

Or we need provide any other information to you? thanks!

Jeff

  • 0
    TI__Genius 16810 points

    Hi Jeff,

    We analyze PCIe applications in terms of insertion loss instead of PCB trace lengths because redriver performance and PCIe specifications are calculated in terms of dB. I don't know the insertion loss per inch for the material the customer is using. You can ask their SI engineers to calculate the total loss in the PCIe link before and after the redriver, including the CPU package loss and endpoint loss if they know, and usually then we can estimate what redriver settings would be a good starting point for tuning.

    Best,

    Evan Su

  • 0 in reply to Evan Su
    Mastermind 7395 points

    Hi Evan,

    Insertion loss as below. Would you please give us default EQ setting suggestion? Thanks!

  • 0 in reply to Jeff YANG
    TI__Genius 16810 points

    Hi Jeff,

    Thanks for the update. For the DS320PR810 link we have 12.8 dB + 8.2 dB = 21 dB shown here. If I roughly assume 8 dB for the CPU package loss and 9 dB for the endpoint that will go into the slot then the total link loss is about 38 dB, which is only slightly above the PCIe Gen 5 loss budget. Therefore I would suggest EQ 0 as a starting point, or if the DS320PR810 would be run in EEPROM/I2C mode they can try the basic EQ Default too.

    For the SN75LVPE5412/421 link we have about 10.5 dB + 10.0 dB = 20.5 dB shown here, and again the total link loss is only slightly above the PCIe Gen 5 loss budget. Typically the SN75LVPE5412/421 redrivers are run in pin mode, so I would suggest EQ 0 as a starting point. But again they can try EQ Default if they are using a mode with I2C.

    Best,

    Evan Su

  • 0 in reply to Evan Su
    Mastermind 7395 points

    Hi Evan,

    Ihave send the schematic set to HW pin mode and 0Bb setting via privacy message. Would you please help us reveiw the circuit? Thanks!

    Jeff

  • +1 in reply to Jeff YANG
    TI__Genius 16810 points

    OK, we will continue in private messages. I will close this thread for now.

    Best,

    Evan Su

  • 0 in reply to Evan Su
    Mastermind 7395 points

    Hi Evan,

    Sure, please check the privacy message for schematic doulble check. thanks!

  • 0 in reply to Jeff YANG
    TI__Genius 16810 points

    Hi Jeff, I received your message and am reviewing the schematic. Please give me another day or so to finish and provide the feedback.

    Best,

    Evan Su