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Altera_Forum
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15 years ago

Matching Cyclone III Signal Impedance to 65Ohm cPCI Traces

I am using an EP3C55F780I7 device to act as an interface between my peripheral board and a cPCI backplane. By specification, cPCI signal traces must be 65 Ohms +/- 10%. In reading through the various...
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Altera_Forum
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15 years ago

One other thing; the CARMA board link that I posted uses bus switches on the cPCI interface to implement hot-swap and a 5V/3.3V universal cPCI interface. Its pretty common to still have 5V cPCI backplanes, and the Cyclone III device is probably not 5V tolerant. If you are building a product, then a universal cPCI interface would be a good thing.

The web link I sent has the PCB layout files (Cadence Allegro), so you can look at the layout with Cadence's free viewer. The routing between the bus switches and your Cyclone III will be much simpler than the PowerPC design. I'd recommend copying the implementation on that board.

Just ask if you have questions.

Cheers,

Dave