Glenn, If you look at the nominals of variables and their tolerances that make up the industry std. +/- 10% on impedances, to get to +/- 5% of SE 50 ohms or DIFF 100 ohms TAKES a lot of improvements on all fronts, as the other emails detail. Under special circumstances (like sorting materials) the +/- 5% or 2.5 ohms for a SE 50 ohms can be reached (we did it for RamBuss at 28 ohms) but is will NOT be robust or a volume production process-just HAND CRAFTED ! Not to mention the difficulty in using a TDR to an accuracy of +/- 5% Note Fabrication Factors For +/- 5 ohms For +/- 2.5 ohms For normal Products For MemBus *1 Core thickness +/- 0.5 mil +/- 0.3 mil *2 Resin Content 50 +/- 3 % 50 +/- 2.5 % *3 Board thickness +/- 3 mil +/- 2 mil after Lamination *4 Di-electric constant 4.4 +/- 0.3 4.4 +/- 0.2 *5 Trace width control +/- 0.8 mil +/- 0.5 mil *6 Cu thickness control +/- 0.5 mil +/- 0.3 mil *7 S/M thickness +/- 0.3 mil +/- 0.3 mil Happy Holden Asian Pacific Materials Glenn Pelkey <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 02/14/2006 02:05 PM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to [log in to unmask] To [log in to unmask] cc Subject [TN] Impedance Spec +/-5% and Cpk of 1.33 Hi folks, Is the industry capable of this requirement? Impedance +/-5% with a demonstrated Cpk of 1.33. This could apply to Single Ended 50 ohms or 100 ohms Differential. Also, this is on a Flex Circuit. Thanks, Glenn --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------