I just signed-up to this list read through most of this thread in the archives. I was intrigued by Istan Novak's post, and the approach he suggests: "One of the published examples replaced about 250 pieces of different-size different-value bypass capacitors with 50 pieces of controlled-ESR 2.2uF capacitors on a CPU card. Apart of two bulks, there was only this single value of bypass capacitor on the board, achieving the minimum number of bypass capacitors, and at the same time effectively suppressing capacitor-to-capacitor, capacitor-to-plane, and modal plane resonances." .... "Measured data supporting the claims/statements (except the last item) on the above list, including more details about implementations, have already been published and is available on line." Can someone (Istan?) post a link to further information on this approach? I am trying to decide on an approach to take on a simple design I'm working on; just a couple of XC2V1000's, some 133MHz SDRAM and half a dozen other devices. HD video processing. Data rates from 74MHz to 165MHz, if you ignore GHz in/out section. What I've read so far from other sources has me a bit confused as to which approach might be the safest. One camp goes for a lot of caps and a half-dozen or more values. Some of my own -basic- simulations tell me that a bunch of 0402 (low ESL, ~0.6nH?) 0.01uF's right on the power pins and a generous number of 150uF, 0.1ohm (~3.4nH?) tantalums distributed throughout the board might do just as well. Frankly, I'm having trouble deciding which way to go. And, now, of course, I read that a valid solution may exist --if I understand it correctly-- without the use of hundreds of small caps. This, of course, is very attractive from many perspectives and I'd like to learn more about it. Finally, a question: How do large valued (>1uF) multilayer chip caps compare to tantalums for high-speed and bulk decoupling? Panasonic has values all the way up to about 100uF but very little performance data (ESR, ESL, SRF?) Thanks, Martin Euredjian eCinema Systems, 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