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@earthlink.net]
> > Sent: Friday, November 03, 2000 6:17 PM
> > To: Robbie Shergill
> > Cc: stds-802-3-hssg@ieee.org
> > 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
> >