[SI-LIST] Re: Package SI vs PCB SI
- From: "Hassan O. Ali" <hassan@xxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Tue, 14 Feb 2006 10:47:37 -0500
Scott,
Thanks for this excellent response.
I have a question for you SI folks:
Am I right to observe that as the data-rates increase beyond 5Gbps, there is an
increasing loss of faith on the previously popular board-level SI tools such as
SpecctraQuest (now Allegro PCB SI), XTK, Hyperlynx, ICX, etc. in favor of
HSPICE used
with field-solver-s-parameter-based inteconnect models?
I was personally surprised to see a notable absence of a focus on such
board-level tools
in the just ended DesignCon 2006. What does this all mean? Is Darwinism
(survival of the
fittest) at play here?
I'd appreciate your responses.
Best regards.
Hassan.
On Feb 14, Scott McMorrow <scott@xxxxxxxxxxxxx> wrote:
>
> Prasad
> The theory is the same,whether you are dealing with packages, system in
> package, MCM or PCB. However, the details will change quite a bit. PCB
> SI tools tend to assume that all routing is orthogonal, or aligned at
> increments of 45 degrees. This makes sense, since orthogonal and 45
> degree diagonal routing are extremely efficient with respect to space
> utilization. An assumption is therefore made by the PCB trace
> extraction tools that two traces are either parallel, or they are not.
> If they are parallel (as defined by parallelism on the 8 compass
> directions) then coupling is calculated. If not, no coupling is
> calculated. For all other traces, with non-45 degree angles, or
> different angles, they are assumed to be uncoupled and independent. As
> I said, for PCB designs, this is often a reasonable assumption. But for
> aggressive PCB design where odd-angle routing is used for maximum trace
> density between parts, and for MCMs and packages, where routing often
> radiates from a die in the center out to the balls, PCB-type trace
> modeling software can be woefully inadequate. That's where you start
> getting into the problem of non-uniform coupled transmission lines and
> imperfect planes with large numbers of perforations.
>
> Current density on package power and ground planes is much higher than
> that on PCB planes, causing additional SSO, SSN problems that are not as
> likely to impact signals on a PCB. As a result, analysis of package SI
> usually involves a combination of 3D solvers, and complete simulation of
> the package signal, power, ground and return paths. Books like Eric
> Bogatin's give you all the basic information that you need. You can
> then expand your knowledge with Brian Young's book, Digital Signal
> Integrity, which has a very good discussion of partial inductance and
> package measurements, Clayton Paul's book, Analysis of Multiconductor
> Transmission Lines, which is still the fundamental theoretical book on
> TEM transmission line modeling, and Luc Martens book, High-Frequency
> Characterization of Electronic Packaging, which gives a good overview of
> modern package characterization techniques.
>
> At the IC level, SI becomes even more difficult. There are no ground
> planes, only power and ground meshes. Multiple modes of propagation can
> exist, including slow-wave mode, where the electric and magnetic fields
> decouple, due to the semiconductor properties of the dielectric, rapidly
> increasing propagation delays, and causing significant dispersion. Ed
> Sayre, III, on this list, has some background in this area. I am sure
> there are others lurking on this list that also have significant
> experience in on-chip SI.
>
> Best regards and happy learning,
>
> Scott
>
>
> Scott McMorrow
> Teraspeed Consulting Group LLC
> 121 North River Drive
> Narragansett, RI 02882
> (401) 284-1827 Business
> (401) 284-1840 Fax
>
> <a
href='http://www.teraspeed.com</a>'>http://www.teraspeed.com'>http://www.teraspeed.com</a
>
>
> Teraspeed® is the registered service mark of
> Teraspeed Consulting Group LLC
>
>
>
> prasadsa wrote:
> > Thanks for all your mails. Many of these books talk about refers to SI on
> > Boards. But i am looking in particularly for books on IC-Package if any or
> > does the same theory (books) holds good on IC-Package also.
> >
> > Regards,
> > Prasad S A
> >
> > ----- Original Message -----
> > From: "Coe, Stephen" <scoe@xxxxxxxxxxxxx>
> > To: <qazi@xxxxxxxxxx>; <si-list@xxxxxxxxxxxxx>
> > Sent: Tuesday, February 14, 2006 2:54 AM
> > Subject: [SI-LIST] Re: Good book
> >
> >
> >
> >> Let me add my 2 cents :=20
> >>
> >> "High-Speed Circuit Board Signal Integrity"=20
> >>
> >> by Stephen Thierauf
> >>
> >> Regards,
> >>
> >> Steve
> >>
> >> -----Original Message-----
> >> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
> >> On Behalf Of Qazi Arif Iqbal
> >> Sent: Monday, February 06, 2006 6:37 PM
> >> To: si-list@xxxxxxxxxxxxx
> >> Subject: [SI-LIST] Re: Good book
> >>
> >> Eric Bogatin's "Signal Integrity Simplified" is another excellent book.
> >>
> >> Qazi=20
> >>
> >> -----Original Message-----
> >> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
> >> On Behalf Of Doug Martens
> >> Sent: Sunday, February 05, 2006 8:25 PM
> >> To: akhilesh.chandra@xxxxxx; prasadsa@xxxxxxxxxx
> >> Cc: si-list@xxxxxxxxxxxxx
> >> Subject: [SI-LIST] Re: Good book
> >>
> >> Black Magic is written by Howard Johnston and it is a good book.
> >> Another good book is from Lee Ritchey called "Right the first Time: a
> >> practical handbook on high speed PCB and System design"
> >>
> >> -----Original Message-----
> >> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
> >> On Behalf Of Akhilesh CHANDRA
> >> Sent: February 5, 2006 9:19 PM
> >> To: prasadsa@xxxxxxxxxx
> >> Cc: si-list@xxxxxxxxxxxxx
> >> Subject: [SI-LIST] Re: Good book
> >>
> >> Hello Prasad,
> >>
> >> In my view for signel integrity best book is "BLACK MAGIC" I =
> >> forgot=3D20
> >> the name of the writer. I will serch it on net and inform you soon.
> >>
> >> Regards
> >> Akhilesh
> >>
> >> prasadsa wrote:
> >>
> >>
> >>> Hi,
> >>> Can you please suggest me a good book for IC-Packaging / SIP Technology
> >>>
> >>> & SI book on the same subject.
> >>>
> >>> Thanks in advance
> >>> Prasad
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