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XAUI Electrical Spec


I propose to use the dimensions of the eye-opening in the Receiver's inputs
in order to express the standard requirements from the Receiver. For
example, the term "Minimum Eye-Height" might be used instead of Vin (min).
The advantage is that it is clear that Min Eye-Height includes the effects
of the Total Jitter in the Receiver.


> -----Original Message-----
> From: Kesling, Dawson W [mailto:dawson.w.kesling@xxxxxxxxx]
> Sent: Friday, November 03, 2000 5:46 PM
> To: stds-802-3-hssg@xxxxxxxx
> Subject: RE: XAUI Driver Spec
> Thank you for brigning this up, Robbie. The 1.6V idea was 
> floated in Austin
> as it was at the XAUI breakout in New Orleans and there were 
> no objections
> in either case. I expect that it will come up again and be 
> officially moved
> in Tampa, so now is a good time to express concerns. I encourage other
> receiver designers to consider the implications and come 
> prepared with an
> opinion.
> -Dawson
> -----Original Message-----
> From: Robbie Shergill [mailto:Robbie.Shergill@xxxxxxx]
> Sent: Friday, November 03, 2000 6:57 AM
> To: stds-802-3-hssg@xxxxxxxx
> Subject: XAUI Driver Spec
> Hello all,
> Last week in Austin the XAUI group decided to change Max 
> Diff. Amplitude to
> 1.6 volts. As I understood it, the rationale for increasing the max
> amplitude 
> was to achieve commonality with the Infiniband spec. Although 
> I agree with
> the spirit of this rationale, I checked the Infiniband spec and found
> that they are trying to drive a cable as well as a backplane with one
> electrical specification; thus the reason for the 1.6v spec. In this
> case, I'm not sure if it is worth matching the Infiniband spec in this
> one area. My feeling is that a driver circuit can be made to drive
> up to either 1.0 volt or 1.6 volt relatively easily; but it would be
> much more troublesome for a (XAUI) receiver to tolerate 1.6 volts 
> *needlessley*.
> So, if the above reasoning is agreed to by others, I would 
> propose that we
> stay with 1.0 volt max. diff. amplitude that is in the 
> current draft 1.0
> (page 119, line 22). 
> -Robbie Shergill
>  National Semiconductor