OCT on Cyclone III

Hey y'all.

I'm doing a Cyclone III to DDR2 interface. It's just the FPGA to one chip, and only about half an inch away, and so I'm trying to save some layout grief by just series terminating everything, and using the FPGA's calibrated OCT. Then I'll put 33R series resistors on the DQ lines at the RAM, 100R across the clock, and call it a day.

Problem is, on a 6 layer stack-up those 50R traces are getting wider than I'd like. Does anyone know if I can use 75R resistors with the calibrated OCT, and just up the few physical resistors accordingly?

Also, as a bonus question, the ALTMEMPHY I generated has two DQS_N pins, even though the Cyclone 3 handbook says that C3 only supports a single ended DQS. Can I just leave those unconnected?

Thanks,

Rob