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DP83848YB: MAC interface impedance

Part Number: DP83848YB

Hi, 

Good day. I hope you are doing fine. 

Our customer is designing using the DP83848YB however they have question regarding the 68-Ω impedance stated on the datasheet (7.2.2.1). They want to know if it is necessary to have 68ohms? or 50 ohms impedance is enough or not? 

I would appreciate your help on this matter. 

Thank you.


Regards,

Cedrick

  • Hi Cedrick,

    The DP83848 requires controlled 68ohm trace impedance on the MII signals. The 50ohm series resistors are recommended to reduce the digital energy along the lines. Both layout guidelines are recommended on DP83848 designs.

    Regards,
    Justin