RE: XAUI IO specs
Kevin,
The Hari I/O spec's from the November meeting are differential p-p. It's
always a confusing spec, but I would simplify it by saying that the
VoDif(max) of 800mV would be 400mV if measured single-ended p-p. (In
essense, the swings are reduced by a little over one-half of the previous
differential PECL swings used in 1GbE.)
In addition the interface is based on AC coupling so common mode voltage is
not necessary.
Regards,
- Richard
> -----Original Message-----
> From: kdemsky@xxxxxxxxxx [mailto:kdemsky@xxxxxxxxxx]
> Sent: Monday, April 17, 2000 8:20 PM
> To: stds-802-3-hssg@xxxxxxxx
> Subject: Re: XAUI IO specs
>
>
>
> Rich,
>
> Thanks for the link to the presentation. I have been looking for that
> presentation for a couple days. It makes things clear to me.
> http://grouper.ieee.org/groups/802/3/10G_study/public/nov99/gh
> iasi_1_1199.pdf
>
> It looks like Ali did a fine job of defining signaling.
> Looking at the
> LVDS levels in the table on page 12, it looks like no signals
> are referred
> to a peak-to-peak need not be defined that way. In fact the
> first four
> items in the LVDS column match the IEEE spec.
>
> It appears by the data in the Hari column that it is a custom
> I/O signaling
> level designed to launch 4x the power (2x voltage and 2x
> current) into the
> trace, counting on attenuation of up to 9.1 dB with "normal"
> FR4, and still
> having about the same signal as required at the receiver end
> of IEEE LVDS.
> I also agree with the deviation from tight termination
> tolerances in IEEE
> LVDS spec, allowing us to integrate the receiver termination
> resistors.
>
> I also looked at the picture on Page 13 of Ali's proposal,
> and noticed that
> you referred to the 0V in the picture as ground. The 0V
> above the X1 point
> is 0V differential and has nothing to do with ground. Now my
> head doesn't
> hurt any more.
>
>
>
> Kevin Demsky
> Mixed Signal and VLSI Development
> IBM Corp.
> 3605 Hwy 52 N
> Dept. QXS Bldg. 050-2
> Rochester, MN 55901
>
> Internal E-mail: kdemsky@ibmusm07
> External E-mail: kdemsky@xxxxxxxxxx
>
> Phone: 507-253-5799
> Fax: 507-253-4966
>
>
>
>
> >Mike,
>
> >On your P.S., I was referencing slide 13 from the proposal
> authored by Mr.
> Ali
> >Ghiasi and Mr. Richard Dugan presented at the November '99
> HSSG meeting in
> >Kauai, HI:
> >http://grouper.ieee.org/groups/802/3/10G_study/public/nov99/g
hiasi_1_1199.pdf
>The legends on the Y-axis come from the table on slide 5. Note the
reference to
>0V, or ground on slide 13.
>Best Regards,
>Rich