DP83867IR: DP83867IR

Hi Ashwini,

The Ethernet PHY 867 has programmable integrated series impedance (programmable through Reg<0x170) which should match with the characteristic impedance of the xMII bus. It is common to use 50ohm buses, but there are many applications with 68ohm too.

In these cases, where the characteristic impedance in not 50ohms, series termination resistors are used.

Ideally, it is recommended to do IBIS simulations on the board, look at signal integrity of the xMII signals and add/change series impedance accordingly.

Please let me take a detailed look at the schematic and provide the feedback by end of Friday.

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Regards,
Gokul.

Hello Gokul,

I am sorry, I didn't understand your point. Should I add series termination in my circuit in TX and RX side or will it work as it is ?

Regards,

Ashwini Kamath

Hi Ashwini,

You can skip the termination resistors if the characteristic impedance of the board traces are 50 ohms on the RX_D, RX_CLK pins.

For series termination on TX_D, TX_CLK pins, please get in touch with the MAC vendor.

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Regards,
Gokul.