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DS25MB100 pre-emphasis recommendation for 1.25Gbps?

Andre Gillard
Other Parts Discussed in Thread: DS25MB100

Hello.

Obviously, the pre-emphasis parameters of the DS25MB100 have been designed for the 2.5Gbps application.

The device datasheet indicates in the introductory features list that the DS25MB100 supports 0.25Gbps to 2.5Gbps operation.

We are using it at 1.25Gbps (for SGMII/1000BASE-X link multiplexing/replication).

What would be the recommended pre-emphasis settings for this bitrate? (comparing with table 4 and 5)

Many thanks and best regards,

André Gillard

  • 0
    TI__Mastermind 43795 points

    Hi Andre,

    The attenuation at 1.25 Gbps is just over 50% of the loss at 2.5 Gbps for most PCB trace/dielectric combinations.  As a rough guide, the table estimates for distance can be multiplied by 1.5x - 2x.

    Do you have an idea about the board losses on the input and output DS25MB100 channels?  We can use this information to help select the best signal conditioning settings for the EQ and Pre-emphasis.

    Regards,

    Lee