Joel
Joel Goergen wrote:
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 am not disagreeing that these were agreed in
the straw poll, I just didn't participated in some
of earlier meeting.
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.
How can you define a channel "backplane" but not
define a minimum attribute for the connector.
There is no reason to de-embed the connector as the connector is part
of the channel. A compliant
channel must meet an specified transmission and reflection property
which include connector.
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.
The methodology specified currently in BP is
suitable for chip to chip applications but not for backplane.
Where do you handle connector effect and multiple reflection between
the connector-IC? In 4Gig FC we addressed some of these issues and do
specify the channel which include the connector.
Thanks,
Ali
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.
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