Just a guess... but the old TV antenna 'twin lead' was 300 ohm impedance... maybe they want a differential impedance between two lines on the board rather than an impedance with respect to a ground plane like micro strip does ??? Bill Brooks - KG6VVP PCB Design Engineer , C.I.D.+, C.I.I. Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 e-mail:[log in to unmask] http://www.dtwc.com http://pcbwizards.com -----Original Message----- From: Mcmaster, Michael [mailto:[log in to unmask]] Sent: Friday, April 15, 2005 2:37 PM To: [log in to unmask] Subject: Re: [TN] impedance value very high I ran this through our field solver. For a 1 mil trace, you'd need a dielectric thickness of about 5 inches to do this. Thick as a brick. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Eric Bonatti Sent: Friday, April 15, 2005 10:28 AM To: [log in to unmask] Subject: [TN] impedance value very high I have a puzzling question for you impedance experts: A customer is asking for a PCB characteristic impedance for a single trace to be 332 Ohms +/- 5%. I've never seen a requirement for an impedance to be this high. Has anyone here seen this before? HyperLynx is choking on this. Thank you in advance for your input, it is greatly appreciated. Eric Bonatti, C.I.D. PCB Designer StrataFLEX Corporation Tel.: +1.416.752.2224 xt.227 Fax: +1.416.752.6719 Toll Free: +1.866.771.7765 E-mail: [log in to unmask] Web: www.strataflex.com --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------