TDP142: What's the maximum inter-pair skew length for 8.1Gbps

Shaquille Chen

Part Number: TDP142

Hi Team,

As we mentioned in datasheet, the maximum inter-pair skew is 2 UI.

We know 2UI for DP1.4 is 2/8.1G = 247ps. How to convert the timing spec to layout length spec?

Shaq.

0 David (ASIC) Liu over 4 years ago

Shaq

For FR4 board material, you can assume 170ps/in for striplines and 145ps/in for microstrip.

So with 247ps, this would translate to 247/170 = 1.45in for striplines and 247/145 = 1.7in for microstrip.

Even though the DP spec allows for a large inter-pair skew, I would still keep the inter-pair skew as low as possible.

Thanks

David

0 Shaquille Chen over 4 years ago in reply to David (ASIC) Liu

Hi David,

How to come up with 145ps/in for 8.1Gbps?

Shaq.

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