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TLK106: Max. Trace length allowed for PHY to PHY connection

Part Number: TLK106

Hi,

We are using the TLK106RHB PHY on the 2 separate boards and we are connecting them with some board to board connectors.

We are using the Magnetics near to the board to board connectors.

We want to know whether there is any trace length limitation from PHY to Magnetics & Magnetics to Other magnetics(on mated board) ?

Can anyone please help me with inputs.

Thanks & Regards,

Nanjunda M

  • Hi,

    If the pcb 2 pcb connection has magentics in path on both PHYs, then no min cable length ( pcb trace) are needed.

    BTW, if you are starting a new design, we recomend to our new 10/100M PHYs : DP83822 or DP83825.

    Regards,
    Geet
  • Hi Geet,

    Thanks for the alternative. We will go with in the next revision as this board is almost at the end of release.

    "If the PCB 2 PCB connection has magnetics in path on both PHYs, then no min cable length ( PCB trace) are needed."
    - not even after the magnetics?

    I have the traces from PHY to magnetics with about 9inch and the Magnetics to the Other magnetics its 9inches.
    So is this is ok?

    Thanks & Regards,
    Nanjunda M
  • Hi,
    I recommend shortened path from Phy to magnetics ( 1 to 3 inch) and differentially routed with complete ground below.

    Regards,
    Geet
  • Hi Geet,

    What will be the effects if its not followed?

    We have the set up as 1 SOM board and carrier board and the PHY is in the SOM board and Carrier board has the Magnetics.

    The signals travel through the 50E standard board to board connectors from Samtec.

    The signals are routed as 100E differential and proper grounds are provided for the signals.

    Kindly help us understand the complexity involved in the effects of the routing distance.

    Thanks & Regards,

    Nanjunda M

  • Hi,

    Our device datasheet is characterised using above limits. So commenting on what is effect is very tough.
    It may violate signal integrity, IEEE Compliance test etc. You may want to run all the test and ensure everything is looking good.

    Regards,
    Geet
  • Ok Geet. Thanks for your valuable inputs.

    We will update the layout.

    Regards,

    Nanjunda M

  • Sure. I am closing this thread. In case you need further assitance, please open a new thread and provide reference to this thread.

    Regards,
    Geet