Larry Smith wrote: >What do these things have in common? They are all examples of circuits >with physical size less than 1/20th of a wavelength of the highest >frequency of interest. And, yes you can assume that a trace is a single >node with no time delay if it short enough compared to a wavelength. We >certainly don't use transmission lines to represent the trace that goes >from one transistor to another. (Well, maybe if we are going a >significant distance across the die, but then it is an RC t-line.. And >yes, on-chip signal integrity is becoming an issue.). Larry- Agree with your recent message, however your comment about: "We certainly don't use transmission lines to represent the trace that goes from one transistor to another.", while true for the most part in digital IC design certainly isn't when you are talking about analog microwave circuits. Short traces can be a significant number of degrees of a wavelength at microwave frequencies and are an important part of matching networks. Not only can they not be ignored, in many circuits they are a necessary circuit component. When discussing these sorts of things you need to keep in mind that what is true in one field of endeavor may not hold across the board. Regards, -Ray Raymond Anderson Senior Signal Integrity Staff Engineer Product Technology Department Advanced Package R&D Xilinx 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: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: http://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