RE: XAUI Electrical Spec
Boaz,
Will specifying eye opening require the prediction of noise and crosstalk
as well as jitter (some of this will show up as jitter, some as DC offset)?
All will affect the eye, but may be very difficult to predict when
accounting for board material, connectors etc.
Also, how much (low crosstalk) distance will be lost by raising this level?
Gerry
-----Original Message-----
From: owner-stds-802-3-hssg@xxxxxxxx
[mailto:owner-stds-802-3-hssg@xxxxxxxx]On Behalf Of Boaz Shahar
Sent: Monday, November 06, 2000 2:48 AM
To: 'Kesling, Dawson W'; stds-802-3-hssg@xxxxxxxx; Eyran Lida
Subject: XAUI Electrical Spec
Dawson,
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.
Regards,
Boaz
> -----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
>