The Xilinx App Note, xapp224, suggests that it's possible to do non-source-synchronous data recovery in a spartan-3 at up to 320 Mbps (320 MHz) -- has anyone ever managed to get this or higher serial speeds working in a spartan-3 PQ208 package? I'm trying to make this work with a 100-ohm differential LVDS link and I can't seem to get my design up past 150 Mbps. I'm totally willing to entertain the idea that I've got signal integrity problems, controlled impedance problems, etc. but I'm worried that the lead inductance on the PQ208 package might make this sort of IO impossible.
Thanks, ...Eric