An old saying: "In theory, there is no difference between theory and practice; however in practice, there is." Dave Wyland Grasso, Charles wrote: >Agreed wholeheartedly Ray. One should not >discount experience .. In the UMR experiments >-taking S11/S21 data - I would not expect >location to be that important. However, >that was only a measure of the performance >of the board and makes no judgement of location >of Ics. > >Best Regards >Charles Grasso >Senior Compliance Engineer >Echostar Communications Corp. >Tel: 303-706-5467 >Fax: 303-799-6222 >Cell: 303-204-2974 >Email: charles.grasso@xxxxxxxxxxxx; >Email Alternate: chasgrasso@xxxxxxxx > > > >-----Original Message----- >From: Ray Anderson [mailto:raymond.anderson@xxxxxxx] >Sent: Monday, August 11, 2003 10:36 AM >To: si-list@xxxxxxxxxxxxx >Subject: [SI-LIST] Re: UltraCAD ESR and Bypass Capacitor Caculator > > > > >Lee Ritchey wrote: > > >>If the location of decoupling capacitors matters, perhaps some >>technical demonstration would prove that. Short of such a >>demonstration, this is speculation and not the sort of thing that >>should be used to make design choices. >> >>It's time to do some good engineering on this subject and do away with >>opinion. The UMR paper is good engineering. Anyone who chooses to >>disagree with it has the burden of showing where it is wrong by using >>some good science. >> >>Lee >> >>Lee Ritchey >>leeritchey@xxxxxxxxxxxxx >>Why Wait? Move to EarthLink. >> >> > > >Or conversely, show that it doesn't matter. > >Take a large system board (say about 24" square) put a bunch of high current >processors and ASICS on the left side of the board. Put all your decaps on >the right side of the board (since you maintain position doesn't matter). > >In this hypothetical case I can just about guarantee the board won't >function properly or pass EMI. Admittedly, it is a contrived case, but I >think it illustrates the point. > >As far as the technical demonstration goes, we have indeed demonstrated to >ourselves that position does matter. > >I'm not attempting to further an argument, but I do feel those who have >responded with viewpoints other than yours shouldn't be chastised and >accused >of spreading unfounded opinion. Don't discount the chance that an opinion >that >differs from yours just might be correct. > >-Ray Anderson >Sun Microsystems Inc. > >------------------------------------------------------------------ >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 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 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 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