Thank you Chris and tank you for your "yapping." You are a valuable contributor to SI-LIST. Roy Chris Cheng wrote: > There is an old Chinese saying along the line of "frogs view of the > world underneath the well". > I am sitting underneath my well and yapping. I think I have said > enough in my last mail and I have nothing else to add. > Those who get what I am saying already got it, there is no point of > repeating. But the topic is sure appropriate, getting some SI > education in the USA. More than a few of us need it. > > ------------------------------------------------------------------------ > *From:* Roy Leventhal [mailto:Roy.Leventhal@xxxxxxxx] > *Sent:* Mon 3/24/2008 1:39 PM > *To:* Chris Cheng > *Cc:* Charlotte and/or Roy Leventhal; olaney@xxxxxxxx; > avtaarenator@xxxxxxxxx; si-list@xxxxxxxxxxxxx > *Subject:* Re: [SI-LIST] Re: Best Signal integrity Schools in the USA > > > Chris, > > For the past six years I have been advocating the use of more simulation > tools among my EMI engineering colleagues (at work and in the IEEE EMC > Society), so I am not unsympathetic to some of your points. > > I find many EMI engineers reluctant to use EDA tools and relatively few > simultaneously cognizant of theory, estimating (yellow pad), simulation, > and measurement in both SI and EMI. Meanwhile, I find continual progress > being made by EDA tool vendors that should be continually evaluated by > the EMI engineering discipline. I also find a growing level of > acceptance of, an interest in, modeling and simulation tools. > > Historically, those EMI EDA tools have not been ready for prime time as > far as EMI engineers are concerned. So they do what they have to do to > get a product to pass regulatory: Test, measure, find and fix, and > iterate until they get a product to pass. > > What I see is that when an EMI engineer is in a test cell measuring > conducted and radiated emissions and susceptibility they are working > with frequency spectrum scans. Those frequency spectrum scans are the > data they have to present, not diagrams of eye opening and other SI > plots. Simulating partial planes an IC package is part of the detailed > design but usually too much detail for them to simulate at the system > level. > > My first question is, can you provide me some insight into your model > abstraction and simplification process? I usually can’t afford > simulating a system down to the gate level when seeking EMI answers. > Some modern CMOS models incorporate around 250 factors for around 50 > elements per gate and I/Os have multiple gates. > > Also, what models are you using for the IC? Are you using Berkeley > SPICE, EKV, PSPICE, S-Parameter, large or small signal, or IBIS, or > what? I’m seeing evidence that factors we can control at the system > level are sometimes interactive AND non-linear and would like to know > the best models to use and their valid frequency, voltage, and > temperature limitations. I suspect that some of the non-linearities are > due to power system noise modulation of my IC I/Os. I also would like to > investigate if there is core-switching noise getting to my I/Os. > > Since I’m trying to correlate with hardware I would also need to know > the distributions of the IC model parameters for the various parts on > the board, as well as the passive components, and the variables for your > dielectric uniformity, trace parameters, etc. I suspect that I’ll have > to do a statistical simulation since in my prototypes I’m not quite sure > which part of the distribution my parts came from. I would like to > repeat the –50 dB you achieved especially since I would expect to verify > the results against hardware. What particular statistical method did you > use in achieving your results? And when you verified those results did > you do it against at least 25 working prototypes to remove the element > of chance? > > How about your measurement repeatability, I assume its good. I know for > myself that when cables are moved just a bit on my test bench my > repeatability is a problem. The movement of objects in my anechoic > chamber and the use of different measurement antennas seem to cause > similar problems. Of course you have modeled all this in verifying your > results, so I seek your guidance since as you state you have many years > of both SI and EMI experience. Since I’m dealing with the safety of an > airplane I can’t be too careful. > > Also, I’m seeing changes in my EMI results with changes in the data > patterns on my boards and changes in the strengths of emitters in > various positions on my boards. So I’m sure that your 50 dB EMI > correlation must account for magnitude and phase at any place in your > measurement chamber. > > One thing that upsets me is a 500 KHz switching power supply in my > system that is producing significant harmonics out to 50 MHz and beyond. > I know that if I simulate its effects that I’ll have to use a SPICE EDA > tool that can model layout structure and converge with resonant > circuits. I haven’t found one readily available that I can import my > layout from Allegro into. Unfortunately, I have to contend with such > beasties operating alongside my moderately fast digital stuff and I > can’t quite do everything I want with the board stackup because I’m > dealing with 10s to 100s of amps in my system, not milliamps to microamps. > > One of my EMI colleagues in another company has become more interested > in simulation (I think I inspired him a little) and who is working with > some first class EMI EDA companies. A real breakthrough was achieved > when his technical contact said “Aha, you want a virtual test bench so > you can directly compare simulation to measurement.” They’re working on > it and achieving some good, if varied results. They’ll need such a tool > when they need to do a quick turn-around on a design iteration. But, he > didn’t indicate 50 dB correlations real soon. They had to simplify the > problem to get it to run in a reasonable time. One thing they didn’t do > is model the antenna. > > Do I believe that EMI modeling and simulation is an absolute necessity? > You bet I do. But, I see a different world with different emphasizes and > needs that will have to be addressed by EDA vendors before the much > criticized and much harried “average” EMI engineer can be successfully > engaged in making greater use of those tools. > > I have many more questions about the issues I raised above and some > others I have. I’m sure that we’ll get into them after you have > instructed me further in my deficiencies as you have already kindly > done. I know that I don’t know near enough in my business and I’m open > to your instruction. > > Best Regards, > > Roy > > > Chris Cheng wrote: > > I walked many miles in EMI and still do. > > My company had never and will never have EMI only design engineers. I > > am responsible for anything that is not 1 and 0 in our system. I don't > > care if it is call SI or EMI. Analog is analog. Any engineer who work > > for me is capable of doing both. > > > As things stand today any EMI engineer can tell you that they can > > > make an entire > > > career on fixing prototype SI/EMI problems based on the same > > > half-dozen principles > > I am still waiting for you to tell me how your EMI engineer can make > > their career out of my examples below. > > > > ------------------------------------------------------------------------ > > *From:* Charlotte and/or Roy Leventhal [mailto:crleventhal@xxxxxxxxxxx] > > *Sent:* Sun 3/23/2008 8:08 PM > > *To:* Chris Cheng; olaney@xxxxxxxx; Roy.Leventhal@xxxxxxxx > > *Cc:* avtaarenator@xxxxxxxxx; si-list@xxxxxxxxxxxxx > > *Subject:* RE: [SI-LIST] Re: Best Signal integrity Schools in the USA > > > > Chris, > > I'm heavily into using modeling and simulation. Check my website: > > http://www.semiconductorsimulation.com > <http://www.semiconductorsimulation.com/> > > <http://www.semiconductorsimulation.com/>. I'm also a great advocate > > of combining EDA tools with the yellow pad for maximum efficiency and > > understanding. > > I recently had/have the opportunity to do some EMI engineering. Before > > either SI engineers cast aspersions on EMI engineers or vice-versa I > > suggest they walk in the others' moccasins a few miles. > > You are right that EMI engineers will have to be better tool users in > > the future. Why don't you help them get started, as I am trying to do? > > Best Regards > > Roy > > > > -----Original Message----- > > *From:* Chris Cheng [mailto:Chris.Cheng@xxxxxxxx] > > *Sent:* Sunday, March 23, 2008 7:52 PM > > *To:* olaney@xxxxxxxx; Roy.Leventhal@xxxxxxxx > > *Cc:* avtaarenator@xxxxxxxxx; si-list@xxxxxxxxxxxxx > > *Subject:* RE: [SI-LIST] Re: Best Signal integrity Schools in the > USA > > > > I would love to learn how to model a multi-giga bit channel with > > accuracy down to -50db with a yellow pad. > > I would love to learn how to predict eye openings of heavily > > loaded DDR2/3 buses with multiple loads and multiple branches and > > driving positions under sso and crosstalk conditions with a yellow > > pad. > > I would love to learn how to model package interconnects that has > > imperfect return reference planes with a yellow pad. > > I would love to learn how to deliver power to a multi-giga hertz > > IC where the power grid and via structure is inherited 2 1/2 and > > 3D with a yellow pad. > > Are you sure we are talking about the same SI work here ? What > > does your average EMI engineer knows about the above anyways ? > > > > -------------------------------------------------------------------- > ---- > > *From:* si-list-bounce@xxxxxxxxxxxxx on behalf of olaney@xxxxxxxx > > *Sent:* Sun 3/23/2008 2:07 PM > > *To:* Roy.Leventhal@xxxxxxxx > > *Cc:* avtaarenator@xxxxxxxxx; si-list@xxxxxxxxxxxxx > > *Subject:* [SI-LIST] Re: Best Signal integrity Schools in the USA > > > > > > The symptom we see today is that many designers are heavily > > reliant upon > > really big, expensive software tools to iterate empirical designs > into > > something workable. The same designer, given adequate understanding > of > > the underlying principles, can often do 90% of the work on a > > yellow pad, > > then use software for cleanup and as a sanity check. When I see SI > > related job descriptions that want work experience with a big list > of > > tools, I can readily guess what the company mindset is: > > substitution of > > tools for competence, and bring in the consultants when they get > into > > trouble. > > > > Orin > > > > On Sun, 23 Mar 2008 14:53:44 -0500 Roy Leventhal > > <Roy.Leventhal@xxxxxxxx> > > writes: > > > Avtaar, > > > > > > It seems strange to me that in the present/coming years of > > > "microwave > > > digital" that we will be graduating logic designers who will be > > > unable to > > > get their signals across a PCB or keep those signals from > > > interfering with > > > other signals. > > > > > > As things stand today any EMI engineer can tell you that they can > > > make an entire > > > career on fixing prototype SI/EMI problems based on the same > > > half-dozen principles > > > from SI/EMI 101. But, fixing problems in hardware instead of > > > catching them in the > > > virtual design not working smart. Part of the challenge of working > > > smart is applying > > > principles and analysis early in development. The logic designer > is > > > best positioned > > > to do that or involve specialist to do it for him or her. > > > > > > First we had the analog age. Then we had the digital age. Now I > > > believe we > > > have the dawning of the age of fast impulse signals driving logic > > > circuits. > > > > > > Meanwhile our schools are, as always, a day late and a dollar > short > > > - not > > > necessarily a few individual professors and schools here and > there. > > > When I got my > > > BSEE in 1962 my professors were still teaching me about vacuum > tubes > > > and had barely > > > started seriously considering teaching transistors. This is > despite > > > the fact that > > > industry had developed viable transistors for nearly a decade by > > > then. > > > > > > The IEEE EMC Society is just now making a credible effort to > address > > > signal > > > integrity. But, signal integrity has been a driving issue for > about > > > 20 > > > years now. > > > > > > It is hard to evolve institutionalized cultures (schools, > > > professional societies, and > > > old-line companies) and thinking. They are, after all, in the > > > business of perpetuating > > > their PAST successes and expertise. > > > > > > The advice about UM-R is good. So is the advice about noting which > > > professors and > > > schools are publishing in the latest technologies. Beyond that, > stay > > > informed and well > > > ead from industry-oriented trade magazines in those latest > > > technologies on your own. > > > Let me suggest High Frequency, Conformity, and the IEEE EMC > Society > > > quarterly newsletter. > > > > > > Lastly, here is a reading list of reference textbooks you can > > > consider perusing: > > > > > > > > > [1] Staff of Agilent Technologies, "Time Domain Reflectometry > > > Theory," > > > Application Note 1304-2 Hewlett-Packard, 2006. > > > > > > See also: > > > > > > Staff of HP, "Time Domain Reflectometry Theory," Application Note > > > 1304-2 > > > Hewlett-Packard, 1988. > > > http://www.lthe.hmg.inpg.fr/medite/5966-4855E.pdf > > > > > > [2] Staff of Agilent, "Manuals: Network Analyzers," Various, > > > down-loadable, Agilent. > > > > > > http://www.home.agilent.com/agilent/facet.jspx?c=153424.i.2&to=80039.k.1&; > <http://www.home.agilent.com/agilent/facet.jspx?c=153424.i.2&to=80039.k.1&;> > > > <http://www.home.agilent.com/agilent/facet.jspx?c=153424.i.2&to=80039.k.1&; > > > > cc=US&lc=eng&no=225 > > > > > > > > > <http://www.home.agilent.com/agilent/facet.jspx?c=153424.i.2&to=80039.k.1 > > &cc=US&lc=eng&no=225> > > > > > > > > > > > > [3] C. Antonescu, P.D. Ewing, "EMI/RFI and Power Surge Withstand > > > Guidance for the U.S. Nuclear Regulatory Commission." > > > > > > [4] Bruce R. Archambeault, "Shielding of Air Vent Holes," page 102 > > > IEEE > > > EMC Society Newsletter, Issue # 215, Fall 2007 > > > > > > [5] Bruce R. Archambeault and James L. Drewniak, /PCB Design for > > > Real > > > World EMI Control/, Springer, 2002. ISBN: 1-4020-7130-2 > > > > > > [6] Bill Ashley, "Using the Network Analyzer as a Grid Dip > > > Oscillator," > > > AN 132 AEA Technology, Inc., 2005 > > > > > > http://www.aeatechnology.com/usermanuals/AN132%20Using%20the%20Network%20 > > Analyzer%20as%20a%20Grid%20Dip%20Oscillator.pdf > > > > > > > > > > > > [7] Eric Bogatin, /Signal Integrity: Simplified/, Prentice Hall, > > > 2004. > > > ISBN: 0-13-066946-6 > > > > > > [8] Marty Brown, "Good Physical Layout Takes Black Magic Out of > > > Power > > > Supply Design," EDA Design Line, 2000. > > > > http://www.edadesignline.com/showArticle.jhtml?article?ID=192200741 > > > > > > [9] Nachyuck Chang, "Theory of Oscilloscope," SNU. > > > http://elpl.snu.ac.kr/csd07/lecturenote/4_dso.pdf > > > > > > [10] Sonia Ben Dhia, Mohamed Ramdani, and Etienne Sicard, > > > /Electromagnetic Compatibility of Integrated Circuits: Techniques > > > for > > > Low Emission and Susceptibility,/ Springer, 2005. ISBN: > > > > > > [11] Mike Eberly and Larry Dunleavy, "Student's Introduction to > the > > > HP8714 RF Network Analyzer," 1998 > > > http://ee.eng.usf.edu/people/dunleavy/references/reading2.pdf > > > > > > [12] Morris Engelson and Fred Telewski, /Spectrum Analyzer Theory > > > and > > > Applications,/ Artech House, 1974. ISBN-10: 089006024X, ISBN-13: > > > 978-0890060247 > > > > > > [13] Y. W. Fowlkes, C. L. Creveling, /Engineering Methods for > Robust > > > > > > Product Design/, Addison-Wesley, 1995. > > > > > > [14] Gene Garat, and Staff of IBM, "EMSAT Rules Checker 16 Rules," > > > Moss > > > Bay EDA and IBM, http://www.mossbayeda.com/EMSAT-Rules.pdf, March > > > 2006. > > > > > > [15] Michael Hiebel, /Fundamentals of Vector Network Analysis/, > > > Rohde & > > > Schwarz, ISBN: 978-3-939837-0 > > > > > > [16] Todd Hubing, "Circuit Board Layout to Reduce Noise Emission > and > > > > > > Susceptibility," University of Missouri - Rolla, March 2006 > > > > > > [17] Multivariate Statistical Analysis: IBM Data Explorer, > > > http://www.research.ibm.com/dx/ > > > > > > [18] Staff, ICEM #62014-3, "Electromagnetic Compatibility Part 3 > > > Integrated Circuits Electrical Modeling," IEC Standard Proposal/, > > > /2002. > > > > > > [19] Staff, IEC # 61000-4-2, "Electromagnetic Compatibility Part > 4-2 > > > > > > Testing and Measurement Techniques - Electrostatic Discharge > > > Immunity > > > Test, IEC, 2001. ISBN: 2-8318-5687-6 > > > > > > [20] Yoonjae Lee and Raj Mittra, "Electromagnetic Interference > > > Mitigation by Using a Spread-Spectrum Approach," IEEE Transactions > > > on > > > Electromagnetic Compatibility, Vol. 44, No. 2, May 2002. > > > > > > [22] Roy Leventhal and Lynne Green, Semiconductor Modeling: For > > > Simulating Signal, Power and Electromagnetic Integrity, Springer, > > > 2006. > > > ISBN 0-387-24159-0 > > > > > > [23] Michel Mardiguian, /Controlling Radiated Emissions by Design, > > > 2^nd > > > Ed.,/ Springer, 2001. ISBN: 0792379780 > > > > > > [24] F. D. Martzloff, "Lightening and NEMP Transient Protection > with > > > > > > Metal Oxide Varistors," General Electric Technical Information > > > Series > > > 82CRD084, 1982. > > > > > > [25] Staff, Maxim, "A Beginners Guide to Filter Topologies," > > > Application > > > Note 1762 Maxim, Inc., 2002, > > > http://www.maxim-ic.com/appnotes.cfm/an_pk/1762 > > > > > > [26] Staff, Maxim, "EMI/EMC Suppression in Audio/Video > Interfaces," > > > Application Note 3882 Maxim, Inc., 2006, > > > http://www.maxim-ic.com/appnotes.cfm/an_pk/3882 > > > > > > [27] Scott Mee, Roy Leventhal, Al Wexler and Mike Ventham, > > > "Simulation > > > for the Suppression of PCB Emissions in Digital Telematics > Devices," > > > > > > ITEM Update 2002, p56. > > > > > > [28] Staff of Mentor Graphics, "Design Rule Checks (DRC) for > > > QuietExpert," Mentor Graphics, June 2005 > > > > > > [29] Staff of National Instruments, "Noise Figure Measurement with > > > the > > > National Instruments RF Signal Generator and RF Vector Signal > > > Analyzer," > > > National Instruments, 2006 > > > http://zone.ni.com/devzone/cda/tut/p/id/3737 > > > > > > [30] Henry W. Ott, /Noise Reduction Techniques in Electronic > > > Systems, > > > 2^nd Ed./, John Wiley & Sons, 1988. ISBN: 0-471-85068-3 > > > > > > [31] Edward Pasahow, /Electronics Pocket Reference, 2^nd Ed/., > > > McGraw-Hill, 1994. ISBN 0-07-048737-5 > > > > > > [32] Clayton R. Paul, Introduction to Electromagnetic > Compatibility, > > > > > > John Wiley & Sons, 1992. ISBN: 0-471-54927-4 > > > > > > [33] R. A. Pease, /Troubleshooting Analog Circuits/, Newnes, 1991. > > > ISBN: > > > 0750694998 > > > > > > [34] R. Perez, Editor, /Handbook of Electromagnetic > Compatibility,/ > > > Academic Press, Inc. 1995. > > > > > > [35] A. Peterson, S. Ray & R. Mittra, Computational Methods for > > > Electromagnetics, IEEE Press & Oxford University Press, 1998. > > > > > > [36] M. S. Phadke, /Quality Engineering Using Robust Design/, > > > Prentice-Hall, 1989. > > > > > > [37] Muhammad H. Rashid, Power /Electronics: Circuits, Devices and > > > Applications, 2^nd Ed./, Prentice Hall, 1993. ISBN 0-13-678996-X > > > > > > [38] Christoph Rauscher, /Fundamentals of Spectrum Analysis/, > Rohde > > > & > > > Schwarz, ISBN: 978-3-939837-00-8 > > > > > > [39] Staff, /Environmental Conditions and Test Procedures for > > > Airborne > > > Equipment, DO-160E,/ RTCA, Inc., 2004 > > > > > > [41] Madhavan Swaminathan and A. Ege Engin, /Power Integrity > > > Modeling > > > and Design for Semiconductors and Systems,/ Prentice Hall, 2008. > > > ISBN: > > > 0-13-615206-6 > > > > > > [42] Staff of Wavecrest, "Oscilloscope - Getting Started," > Wavecrest > > > > > > 2001. > > > > > > http://www.wavecrest.com/technical/VISI_6_Getting_Started_Guides/6oscillo > > scope.pdf > > > > > > > > > > > > [44] Wikipedia, "Electronic test equipment" > > > http://en.wikipedia.org/wiki/Electronic_test_equipment > > > > > > [45] Wikipedia, "Insulated-gate bipolar transistor" > > > http://en.wikipedia.org/wiki/IGBT > > > > > > [46] A. B. Williams & F. J. Taylor, /Electronic Filter Design > > > Handbook, > > > 3^rd Ed./, McGraw-Hill, 1995. > > > > > > [47] Staff X2Y, "App Note # 3008, V1, Get the Most from X2Y > > > Capacitors > > > with Proper Attachment Techniques," X2Y Attenuators, LLC. > 2/23/2006. > > > > > > > > > > > -------------------------------------------------------------------- > ---- > > > > > > <#_ftnref1> > > > > > > > > > Good Luck > > > > > > Roy Leventhal > > > > > > > > > > > > Avtaar Singh wrote: > > > > Gurus: > > > > Can someone please name the Top 5 Signal Integrity schools in > the > > > US, for > > > > me? > > > > > > > > Thanks for the kind help! > > > > > > > > Regards, > > > > Avtaar > > > > > > > > > > > > > ------------------------------------------------------------------ > > > > To unsubscribe from si-list: > > > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject > > > field > > > > > > > > or to administer your membership from a web page, go to: > > > > //www.freelists.org/webpage/si-list > > > > > > > > For help: > > > > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > > > > > > > > > > > List technical documents are available at: > > > > http://www.si-list.net <http://www.si-list.net/> > <http://www.si-list.net/> > > > > > > > > List archives are viewable at: > > > > //www.freelists.org/archives/si-list > > > > or at our remote archives: > > > > http://groups.yahoo.com/group/si-list/messages > > > > Old (prior to June 6, 2001) list archives are viewable at: > > > > http://www.qsl.net/wb6tpu > > > > > > > > > > > > > > > > > > > > > > > ------------------------------------------------------------------ > > > To unsubscribe from si-list: > > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject > > > field > > > > > > or to administer your membership from a web page, go to: > > > //www.freelists.org/webpage/si-list > > > > > > For help: > > > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > > > > > > > > List technical documents are available at: > > > http://www.si-list.net <http://www.si-list.net/> > <http://www.si-list.net/> > > > > > > List archives are viewable at: > > > //www.freelists.org/archives/si-list > > > or at our remote archives: > > > http://groups.yahoo.com/group/si-list/messages > > > Old (prior to June 6, 2001) list archives are viewable at: > > > http://www.qsl.net/wb6tpu > > > > > > > > > > > > > > ------------------------------------------------------------------ > > To unsubscribe from si-list: > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject > field > > > > or to administer your membership from a web page, go to: > > //www.freelists.org/webpage/si-list > > > > For help: > > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > > > > > List technical documents are available at: > > http://www.si-list.net <http://www.si-list.net/> > <http://www.si-list.net/> > > > > List archives are viewable at: > > //www.freelists.org/archives/si-list > > or at our remote archives: > > http://groups.yahoo.com/group/si-list/messages > > Old (prior to June 6, 2001) list archives are viewable at: > > http://www.qsl.net/wb6tpu > > > > > > > > This email and any attachments thereto may contain private, > > confidential, and privileged material for the sole use of the > > intended recipient. 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