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DP83822I: intra-pair and inter-pair routing layout

Aaron Spaete
Expert 4391 points
Part Number: DP83822I
Other Parts Discussed in Thread: DP83867E

Team, 

My customer has the following question. 

We are working the layout and route of the Ethernet interfaces on our prototype modules. Do you have a TI app note that defines the Ethernet routing RX/TX requirements of  intra-pair and inter-pair trace length and matching between the PHY devices, Magnetics, and Port Connector (RJ45)?

 For reference, here are the devices that we are using: dp83867e, DP83822IRHBT.

Regards,

Aaron

  • 0
    TI__Expert 5425 points

    Hi Aaron,

    We currently do not have an app note, but I can provide some suggestions for the MDI trace requirements:

    1. All traces should have a trace length of less than 2 inches.
    2. For both intra-pair and inter-pair, length match within 50 mils for 1000M applications, or 100 mils for 10/100M applications
    3. Ensure a controlled impedance of 100 ohms differential.
    4. Recommend placing a keepout of size 5*w around the traces, where w is the width of the trace.

    Regards,

    Adrian Kam

  • 0 in reply to Adrian Kam
    TI__Expert 3595 points

    Hi Aaron,

    I'm also linking an app note that focuses on PHY design checks: https://www.ti.com/lit/an/snla387/snla387.pdf

    It reiterates what Adrian already replied, in addition to a few other key considerations.

    Thanks,

    Lysny