DP83867IS: RGMII Length

Ryan.Bishop

Part Number: DP83867IS

Hello,

There is a note on page 94 that said "Keep traces as short as possible; less than 2 inches is recommended with less than 6 inches as maximum length" for the RGMII.

One of our customers has a main board that uses 7 inches and by the time it gets to the PHY on their daughter board there is another 2 inches. So there is a total of 9 inches maximum.

I'm hoping the guidelines are conservative. The customer's previous PHY from a competitor allows 15 inches maximum for RGMII trace lengths. Can we make this work?

Thank you,
Ryan B.

over 6 years ago

0 Geet Modi over 6 years ago

TI__Mastermind 26320 points

Hi Ryan,

RGMII is high speed 125Mhz DDR interface. Long trace may get us in to violating some of the rise/fall timing and can cause issue. Suggest to measure the RGMII timing on the sink side for both TX and RX to ensure these are with in specs.

Regards,
Geet

0 Geet Modi over 6 years ago in reply to Geet Modi

TI__Mastermind 26320 points

Hi,

I am closing this thread. Incase you need further assistance, please open new thread and provide reference to this thread.

Regards,
Geet

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DP83867IS: RGMII Length