Re: 16-bit 625Mbaud XGMII
JR Rivers wrote:
>
> How about 1.25 Gbaud LVDS?
On the one hand, the telecom sector is going to LVDS in a very
big way. Which means that all of those spiffy medium-interface
suppliers will be happy with it.
On the other hand, LVDS is utterly horrid for CMOS. Locking
in a 2.4v common-mode range for as far as the eye can see is
a death sentence for I/O performance scaling.
> At 03:07 PM 3/20/00 -0800, Andreas Bechtolsheim wrote:
>
> >Jaimie: you need to count package pins, not signal I/Os.
> >
> >Your 625 MHz XGMII using LVDS differential signalling
> >requires 76 pins, which is the same pincost as the
> >312.5 MHz XGMII using single-ended drivers.
> >
> >In addition, you would need to run at least part of
> >your logic at the 625 MHz which is significantly
> >more difficult to implement than staying with a
> >clock frequency of 312.5 MHz.
> >
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