Frank, 1) Your fab shop will need need to test the impedance of the sample traces - either on board or on a coupon added to the panel - using TDR. Most fab shops these days have the equipment to perform this test. A printed report, listing serial number and test measurements should be requested. 2) Unless your incoming inspection is also equipped with TDR, there's not much they can do. 3) If coupons are used for impedance testing, these can certainly be supplied to an independent lab for verification. Hope this helps...Andy Slade ______________________________ Reply Separator _________________________________ Subject: [TN] Micro-strip and Controlled Impedance Author: "Kimmey; Frank" <[log in to unmask]> at SMTPLink-Hadco Date: 01/08/99 10:25 AM Hi all, I need a little help here. After doing RF microstrip designs for the past 5 years I need now to control impedance. We have in the past been able to tweek the design to accommodate for fab tolerances, this luxury is now gone. I am working on a critical circuit that will use 0603 components and 11 printed inductors. What I need to know is: 1.) What tests should I have performed by the vendor? 2.) What tests can my in-coming QA guys do? 3.) What differences should there be in my Fab notes? 4.) If I call out 50ohm impedance should I accept a cert. of conformity or have additional tests run (outside lab)? 5.) Anything else I need to worry about? Thanks for your time and answers FNK Frank N Kimmey C.I.D. EM Designer C & K Systems, Inc. 916-353-5366 [log in to unmask] ################################################################ 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's web site (http://www.ipc.org) "On-Line Services" section 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################