Re: XAUI Driver Spec
Hi
Sensitivity of 200 mV would be under worst case jitter and amplitude
conditions.
Thanks,
Ali
Broadcom
Boaz Shahar wrote:
>
> I See.
> The question is: the 200mv signal at the receiver inputs is the size of the
> eye pattern (mesured under standard jitter conditions), or the value does
> not include jitter.
> Boaz
>
> > -----Original Message-----
> > From: Ali Ghiasi [mailto:aghiasi@xxxxxxxxxxxxx]
> > Sent: Monday, November 06, 2000 4:15 AM
> > To: Boaz Shahar
> > Cc: Robbie Shergill; stds-802-3-hssg@xxxxxxxx
> > Subject: Re: XAUI Driver Spec
> >
> >
> >
> > Hi Boaz
> >
> > The 900 mV is due to signal attenuation as FR4 are predominately
> > loss limited.
> >
> > Thanks,
> >
> > Ali
> >
> > Boaz Shahar wrote:
> > >
> > > Hello Ali,
> > > 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?
> > >
> > > Thx.,
> > > Boaz
> > >
> > > > -----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
> > > >
> > > >
> > > >
> > > > HI
> > > >
> > > > The receiver max amplitude need to be higher than
> > transmitter to allow
> > > > some
> > > > margin and protection. Very likely in Tampa the max transmit
> > > > amplitude
> > > > will
> > > > be raised, where 1.6 V max will become more logical. The
> > 1.6 volts is
> > > > p-p
> > > > diff. so each wire only drives 800 mV.
> > > >
> > > > Thanks,
> > > >
> > > > Ali
> > > >
> > > > Broadcom
> > > >
> > > > 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
> > > >
> >