FreeLists / si-list / [SI-LIST] Re: Paper on BGA crosstalk and power system

["Zhiping Yang" <zhiping@xxxxxxxxx>]

Hi Dr. Howard and Mark,

First, thanks for your contributions and sharing on package crosstalk.  It
is very good and interesting.  Here is a few comments I have on your paper
and measurement:

1. As far as I know, there are two major factors in package design which
could impact the package performance on the crosstalk and power/ground
bounce.  They are power/ground pin assignment and package stackup.  Your
paper and measurement addressed the first topic very well, but did not touch
the second topic.  It may be a little bit hard for you to get stackup info
from your competitor, but you can still verify it by building Xilinx
packages with different stackups.  Please also consider the impact from the
PCB board stackup too.

2. On page 4, you proposed to lump the crosstalk and ground/power bounce
into one single "crosstalk" term.  I think it works fine in your example.
In the real design, separating them is still possible and could be very
helpful for the package designer to know the reasons behind the problems, so
the design can be improved in next release.

The above is my $0.02 inputs.  I also would like to hear the feedback from
other SI experts on this list.  Thanks.

Best regards,

Zhiping




----- Original Message -----
From: "Mark Alexander" <mark.alexander@xxxxxxxxxx>
To: "SI List" <si-list@xxxxxxxxxxxxx>
Sent: Wednesday, March 02, 2005 9:05 AM
Subject: [SI-LIST] Paper on BGA crosstalk and power system


> Hey all,
> Some of you may have already attended this, but I wanted to draw your
> attention to a WebCast seminar and accompanying paper that was released
> yesterday.  The topic is a joint study by Xilinx and SigCon (Howard
> Johnson) of crosstalk and power system noise in FPGA systems.
>
> The paper:
> http://www.xilinx.com/products/virtex4/pdfs/BGA_Crosstalk.pdf
>
> The archived WebCast (might not be available until tomorrow):
> http://www.xilinx.com/events/webcasts/tol/01feb05.htm#3
>
> The WebCast is a full hour with Q&A at the end; the paper /seems /long
> but is actually pretty easy to read.  I especially like Howard's
> explanation of the crosstalk model of power system noise and why it's
> appropriate to the large BGA scenario.
>
> I'd be very interested to hear feedback from people on the list --
> factors we didn't consider, overall usefulness of the information
> presented, ideas for future studies on the same measurement platform.
>
> Thanks!
> mark
>
>
>
>
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