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Original question:

Recommendation for a Retimer

DS280DF810: Recommendation for a Retimer

pavan kumar15
Prodigy 50 points
Part Number: DS280DF810

Team,

I am using 12 retimers (6 in transmit path and 6 in receive path).

The retimers in receive path have the eye a bit closed. So I made the following settings in RX EQ/DFE:

1. enabled VGA slection bit and

2. continuous DFE adaption.

I got an improved eye.

Now the question is what happens if I use the same setting in transmit path even though I had a good eye without these settings. I want to know the impact, if the impact is on power I don't mind.

Please let me know if there is any other impact other than that.

Thanks,

Pavan G.

  • 0
    TI__Guru* 93670 points
    Hi Pavan,

    Could you please clarify as to what you mean by "transmit path"? Are you referring to transmit differential signal pairs such as TXxP and TXxN?

    On transmit differential pair FIR filters and VOD are the only parameter or knobs which control signal conditioning. DFE and VGA are on the input side of the device.

    Regards,,nasser
  • 0 in reply to Nasser Mohammadi
    Prodigy 50 points

    Hi Nasser,

    The path from backplane to retimer to optics is transmit path.

    The path from optics to retimer to backplane is receive path.

    The receive path retimers are set with VGA and Continuous DFE adaptability for better eye.

    I want to use the same settings for retimers on transmit path also even though the eye looks good with default settings for uniformity.

    Thus I want to understand how does turning on VGA and continuous DFE adaptability affect my board design.

    Thanks,

    Pavan G.

  • 0 in reply to pavan kumar15
    TI__Guru* 93670 points
    Hi Pavan,

    Since signal is going through two different media, CTLE setting may or may not be the same.

    Suggestion is to use HEO/VEO as a criteria to determine optimum settings. Which ever settings provide maximum HEO/VEO then we should use that setting.

    Regards,,nasser