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Hi,
What is Stratix4 GX PCIe2.0 channel trace impedance recommendation?
Please can you suggest, Is it 100Ohm impedance differential signal pcb trace or 85Ohm?
Regards,
Sachin.M.Kurawatti
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It's the PCIe spec that specifies the impedance.
From memory for PCIe you want 60 Ohm single ended (+/- X%) , 100 Ohm differential (+/- Y%), although length matching the tracks is more important than exact impedance matching.
I think I read somewhere that you're better to have a lower differential impedance (80 Ohm) as any changes in routing (ie necking to get between balls) gives a smaller % discontinuity than with 100 Ohm tracks.
Sorry if this is a bit vague but I'm at a client's so don't have all the info here.
Nial.
Honored Contributor
