DP83822I: PCB layout design guideline for Ethernet 100Base-TX Differential pair

Rajesh Ketharaju

Part Number: DP83822I

Tool/software:

Hi,

I'm looking for PCB layout design guidelines for Ethernet 100BASE-TX differential pair Tx and Rx lines.

Both pair of Tx and Rx should be length matched with respect to each other or only Tx and only Rx individual pair should be length matched ?

Regards,

Rajesh.

0 J 23 days ago

Hi Rajesh,

We recommend both pairs are length matched to each other and within the differential pair ideally.

Best,
J

0 Rajesh Ketharaju 20 days ago in reply to J

Thank you for your response.

Is there any tolerance between them for length matching and what is the maximum length of these pair ?

0 J 20 days ago in reply to Rajesh Ketharaju

Hi Rajesh,

For 1G, we typically recommend within 20 mil and within 50 mil for 100/10M PHYs on inter pair. This is to ensure that there is system margin with the cable and the link partner connected.
Please refer to this link for more information: https://www.ti.com/lit/an/snla387/snla387.pdf?ts=1755481624530&ref_url=https%253A%252F%252Fwww.bing.com%252F

Best,
J

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