I did some
full wave analysis and circuit analysis. Both agree. If you take 40” of differential
line that’s -60 DB SDDS11 alone and put 0.1 pF of uncompensated load at
the port launch points you get about -12 db SDD11 at 15 GHz.
Your
connector and mounts must be real good.
..>Rich
From: owner-stds-802-3-blade@listserv.ieee.org [mailto:owner-stds-802-3-blade@listserv.ieee.org]
On Behalf Of Joel Goergen
Sent: Wednesday, August 18, 2004
11:51 AM
To:
STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] Revised
S-parameters
Ali,
We have been focusing on this for several months now. I think Steve has
presented nothing new that hasn't been published and, at a min, agreed to in
some form of straw poll.
I would like to offer a thought ...
For the channel ... we use the SMA and SMA foot print that allows for a clean
launch. At both ends of the channel. This allows us to see the
SDD11/SDD22 without doing a major de-embedding and still allow for freq to
12.5Ghz.
For the tp1 and tp4 ... we then let the tx (tp1) handle the BGA and via, the
rx(tp4) handle the via, both cap pads, both via and BGA pad. It will be
easier to do the de-embedding and specify the SDD11/SDD22 as seen by the chip
from the channel.
Just my own thoughts .....
-joel
Ali Ghiasi wrote:
Steve
Looking at your channel model, I see the return loss up to 15 GHz is
better than 12 dB.
How do you get -12 dB return loss at 15 GHz with connectors, what kind
of connector
are you assuming? The most challenging effect are the primary
reflection between
silicon and the connector at this speed.
Thanks,
Ali
Stephen D. Anderson wrote:
All:
I updated the synthesized S-parameter files that I presented in
Portland.
The new revision provides a much better NEXT file. The Thru
file was also improved so that SDD11 magnitude has ripples. You may
recall that the previous SDD11 magnitude was flat over most frequencies
of interest and that this was viewed as unrealistic.
These are intended to match the NEXT and Thru templates that we
have
thus far agreed on.
If you see anything blatantly wrong with the files, please let me
know.
Regards,
Steve A.