*** OUR NEWSLETTERS GOT BACKED UP IN FREELISTS.ORG LAST WEEK, SO YOU'RE GETTING TWO FOR THE PRICE OF ONE TODAY. ENJOY!*** _____________________________________________________ BYPASS ARRAY MODEL HIGH-SPEED DIGITAL DESIGN ? online newsletter ? Vol. 6 Issue 02 I'll be at DesignCon 2003 next week in San Jose, learning lots of new things as always. Hope to see you at the show. Ralph Cavin has me scheduled to talk on a panel about University Education. I also will appear with Henri Merkelo talking about the new reality of multi-level transceivers for backplane applications. The following week brings another reprise of the ever-popular High-Speed Digital Design seminar at the Embassy Suites Hotel in Milpitas. See www.sigcon.com for details. ______________________________________________________ BYPASS ARRAY MODEL Daniel Paradis writes to the si-list: Is-there a Mathcad model available to calculate the impedance magnitude of a bypass capacitor array? I am specifically referring to sec 8.2 of "High Speed Digital Design". ______________________________________________________ Dr. Johnson replies: Thanks for your interest in High-Speed Digital Design. This summer I received a very nice Excel spreadsheet based on the approach outlined in section 8.2 equations. The spreadsheet was developed by JP Nicholls of Powerwave UK Ltd. It takes into account the inductance of your power- supply wiring, any bulk-decoupling capacitors, a uniform bypass capacitor array, and the natural capacitance of your power and ground planes. JP's spreadsheet produces a beautiful color version of my figure 8.9 showing the impedance of each element and also the composite impedance of all four elements taken in parallel. Once you see how it works you can modify it to do lots of other combinations. The spreadsheet runs on Windows using Excel 2000. It handles all the calculations quite nicely using the complex-maths functions in Excel. www.sigcon.com/pubs/news/PowerSystemImpedance.xls I love the fact that this has been done on an Excel spreadsheet because, as much as I like to use MathCad, I must admit that Excel is much more widely disseminated. Thanks, JP. Best Regards, Dr. Howard Johnson ______________________________________________________ Dr. Johnson is the featured signal integrity columnist for EDN Magazine (http://www.ednmag.com). We archive all his EDN archives at http://sigcon.com under "Archives". High-Speed Signal Propagation: More Black Magic is now available for pre-sales at Barnes and Noble, www.barnesandnoble.com If you have an idea that would make a good topic for a future newsletter, please send it to hsdd@xxxxxxxxxxx To subscribe to this list send an email to hsdd-request@xxxxxxxxxxxxx with 'subscribe' in the subject field. To unsubscribe from this list send an email to hsdd-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field. Newsletter Archives: http://www.sigcon.com/ Copyright 2002, Signal Consulting, Inc. All Rights Reserved.