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DP83620: Usage of ETH Phy DP83620 in FX mode

ANIKET
Prodigy 340 points
Part Number: DP83620

Hi,

We plan to use the ETH Phy DP83620 in FX mode. Instead of using a FOT, we plan on using LVPECL/CML to M-LVDS converters for a multi drop Ethernet backplane design”. Implementation is given in below flow chart.


 

    1. Does TI have any ref implementation/ design/ any similar attempt with other customers in implementing an Ethernet Multidrop via LVDS using the above idea.
    1. In Section 7.1.2 of Ethernet PHY datasheet, dp83620 Datasheet, that discusses the need for encoding to avoid FCC issues when using Copper Mode. Also referring Section 7.3.1 in same document we see this Scrambler and MLT3 encoding is bypassed in FX mode. Hence in FX mode this may be OK, but we are now still continuing to us this in LVDS mode. Would like to understand if there is any documented evidence of EMI/EMC impact if we implement this way.

  • 0
    TI__Mastermind 26320 points
    Hi Aniket,

    I am not clear how they will be able to get a multirdop Ethernet with this implementation as 100Base-TX inherenet is p2p. Can you please explain why mutidrop is needed and how they plan to implement ?

    We have seen customer implement back-plane communication without using magnetics ( using capacitive coupling) .

    Also, any specific reason to choose DP83620 as we have our new part DP83822 offering similar features.

    Regards,
    Geet
  • 0 in reply to Geet Modi
    TI__Prodigy 340 points
    Hi Geet,

    Customer response is below:

    The multi-drop is needed as we don’t want to use switch to interconnect different nodes on the backplane. It is achieved using MLVDS transceivers instead of fiberoptic transceivers.
    DP83620 is a an instance of PHY to illustrate the concept and not specifically our requirement. We can go ahead with the latest version also.
  • 0 in reply to ANIKET
    TI__Mastermind 26320 points
    Hi Aniket,

    It will be interesting to understand how these will be connected Electrically. Also, do they plan to bypass the 100Base-FX PCS signalling used for Link-Up ?

    Regards,
    Geet
  • 0 in reply to Geet Modi
    TI__Mastermind 26320 points
    Hi,

    I am closing this thread. In case of further assistance, please open new thread with reference to this thread.

    Regards,
    Geet