RE: XAUI Driver Spec
I have a question in regards to your presentation for Tampa:
You assert that the 900mv signal is attenuated to 200mv due to a loss of
13db. This loss includes Jitter? That is, the height of the eye pattern in
the receiver's input is 200mv or less then that due to jitter?
> -----Original Message-----
> From: Ali Ghiasi [mailto:aghiasi@xxxxxxxxxxxxx]
> Sent: Friday, November 03, 2000 6:17 PM
> To: Robbie Shergill
> Cc: stds-802-3-hssg@xxxxxxxx
> Subject: Re: XAUI Driver Spec
> The receiver max amplitude need to be higher than transmitter to allow
> margin and protection. Very likely in Tampa the max transmit
> be raised, where 1.6 V max will become more logical. The 1.6 volts is
> diff. so each wire only drives 800 mV.
> Robbie Shergill wrote:
> > 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