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DS125DF410: Equalizer fine tuning

Karthikeyavelan kandasamy
Prodigy 80 points
Part Number: DS125DF410

Hi ,

We want to fine tune the Equalizer of DS125DF410 and topologies are as below.

BCM switch --> Retimer --> QSFP+ cable  --> retimer --> BCM Switch.

We are using the EEPROM for Equalizer setting. Please let me know the best method of equalizer fine tuning.

 

Regards

Karthik

  • 0
    TI__Mastermind 24272 points

    Hi Karthik,

    What is your current retimer configuation?  Are you experiencing bit errors?

    For the egress retimer, if the channel between the BCM switch and retimer has low insertion loss, it may be advantageous to manually set the CTLE value.  You may also want to tune retimer TX to ensure optimal eye at the QSFP port.

    For the ingress retimer, I would recommend using adapt mode 2 with DFE enabled.  This enables the retimer to adapt CTLE and DFE in order to find the best equalizer settings.  You will also want to tune retimer TX to ensure optimal eye at the BCM switch.

    Thanks,
    Drew

  • 0 in reply to Drew Miller1
    Prodigy 80 points

    Hi Drew,

    Yes we have errors, 

    optical QSFP+ cable is errorfree and Copper QSFP+ cable has errors.

    we will try your suggestions and let you know.

    Regards

    Karthik

  • 0 in reply to Karthikeyavelan kandasamy
    TI__Mastermind 24272 points

    Hi Karthik,

    Copper QSFP+ typically has more insertion loss than optical modules.  I expect adapt mode 2 to help with this.  Please keep me updated.

    Thanks,
    Drew