DS80PCI800: PCIE length match

daniel

Part Number: DS80PCI800
Other Parts Discussed in Thread: DS80PCI810

Hi Team,

PCIe Board Design Guidelines from Intel: All differential pairs should be length matched to within a maximum of 7 inches of one another on the system board, though a smaller delta (~0 - 3 inches) is generally preferred.

On my PCIe x16 case, there are over 5" length mismatch. Whether DS80PCI800 has requirement for length match?

Any DS80PCI800 can do to compensate this mismatch?

Thanks

over 7 years ago

0 Lee Sledjeski over 7 years ago

TI__Mastermind 43795 points

Hi Daniel,

The DS80PCI800 is not impacted by length mismatch since it is not looking at the protocol. It is only doing a linear equalization of the signal.

From a specification perspective it will not help or hurt the length mismatch in the system.

Regards,

Lee

0 daniel over 7 years ago in reply to Lee Sledjeski

Genius 5095 points

Hi Lee,

Thanks for the reply.
Does DS80PCI800 linear? I think DS80PCI810 is linear but DS80PCI800 is limited.

Thanks

0 Nasser Mohammadi over 7 years ago in reply to daniel

TI__Guru* 93570 points

Hi Daniel,

You are correct. Normally linear drivers like DS80PCI810 have less gain. On the other hand, limiting devices have much more gain.

Regards,,nasser

0 daniel over 7 years ago in reply to Nasser Mohammadi

Genius 5095 points

Hi Nasser,

Thanks for confirm.
So If I use DS80PCI800, Does it not impacted by length mismatch since it is not looking at the protocol? I am confused since It is not doing a linear equalization of the signal like DS80PCI810.

Thanks

0 Lee Sledjeski over 7 years ago in reply to daniel

TI__Mastermind 43795 points

Hi Daniel,

The DS80PCI800 is also a linear equalizer, the output driver on the DS80PCI800 is not as linear. Both devices do the same job. The DS80PCI800 has more gain and not as good linearity. the DS80PCI810 has less gain and better linearity.

Regards,

Lee

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DS80PCI800: PCIE length match