Al, The formula in the IPC-D-275 was obsoleted by the IPC-SM-782, which in turn was updated with the release of the IPC-SM-782A. The formulas are available electronically in the IPC-EM-782 which is a spreadsheet version of the tables in IPC-SM-782A. I encourage you to look at the web calculator on the IPC web site: www. ipc.org. This is a realtime calcualtor in as that it contains many user defined components and land patterns. These patterns follow the land pattern principles defined in IPC-SM-782. Users have reported that they save the html document and then run it through a filter to directly drive thier CAD system land pattern generator. Please contact me directly if you should need any further assistance. Regards, Gary Ferrari Executive Director IPC Designers Council (860) 350-9300 Fax (860) 350-9309 [log in to unmask] >>> "Arellano, Albert D" <[log in to unmask]> 06/01/98 12:54PM >>> IPC support, I've been evaluating methods of inputting IPC standards into our CAD systems software. The formula approach intrigued me because of it's minimal amount of input required from a potential user. Problem is... from looking through IPC-SM-782 manual (published in 1996) I don't find a straight forward formula for a chip resistor. In your IPC-D-275 publication (dated September 1991) I've found a formula for chip resistors within section 5.3.4.3 that's very clear. Upon using this formula, when I plug in values from SM-782 subsection 8.1, heading 4.0, for the 1206 chip resistor, results doesn't match the land pattern dimensions supplied on the following page. To shorten the request, what I would like is the formula used for generating the chip resistor land pattern values for IPC-SM-782 manual. If the formula does not reside in the SM-782 spec, please E-mail, or Fax it to me. If you have any questions.. please E-mail, or call me. - Thanks for your help.... Al Arellano E-mail = [log in to unmask] Phone = (303) 581 2407 FAX = (303) 581 9973 ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################ ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################