Joel - I haven't seen the standard on this coupon , so keep on searching 1) call you favorite board house and ask them what type of eq they have and ask them for the correct footprint for their TDR equipment 2) ask agilient / other vendors also - how do they expect their adapter to mount to a board 3) I have seen 6" as a min length (although it's been a while since I used a coupon) 4) if you have to put traces for these tests, obviously you need one trace (no vias) per signal layer 5) I remember the footprint expected to be something like a SMA board mounted type... I would like to see what the big board houses do , so, I'm going to follow this thread. good luck. Keith Kowal 781-593-0199 (h) www.product-designs.com > From: joel@xxxxxxxxxx > To: si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] IPC standard for impedance coupons > Date: Thu, 9 Dec 2010 10:46:21 -0800 > > Does anybody know what the applicable IPC spec is for impedance testing and > coupons? > We have been referencing IPC-2221 on our PCB drawings but I could not find > anything on impedance coupons in this standard. > > It seems like IPC-2141A might be what I am looking for but I don't have a > copy but have ordered it. > > Also how closely should a coupon match the actual board? If there are > controlled impedance traces that transition between various layers, should > the coupon include the same layer structure including vias, or is there a > separate impedance test done for each layer? > > > > Thanks - Joel > > > > > > > > ------------------------------------------------------------------ > 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: > //www.freelists.org/webpage/si-list > > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > > List technical documents are available at: > http://www.si-list.net > > List archives are viewable at: > //www.freelists.org/archives/si-list > > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > ------------------------------------------------------------------ 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu