The only specified "rule" is in IPC-D-275 Section 5.3.1.2 Conductor Routing. It states that for conductors that change direction with less than a 90 degree included angle should have their internal and external corners rounded. I've been designing boards for 18 years and have never run into a "T" problem from either a design or manufacturability standpoint. > ---------- > From: R. Christopher Lott > Sent: Thursday, July 23, 1998 3:50 PM > To: [log in to unmask] > Subject: [TN] Conductor Routing Question > > First of all, I'm an engineer and don't do board layout every day. > Please forgive what may be a dumb question... > > I have a nagging recollection in my mind that PWBs designed to > MIL-STD-275 (now IPC-D-275) had a special requirement on the > conductor routing. Namely, that all conductor traces have to > begin and end on a land. That is, no conductor "tees" are > permitted. > > Now that I may be making such a board, I reviewed both MIL-STD-275 > and IPC-D-275, and don't find this to be the case. The only remotely > similar remark is in section 5.3.1.2 Conductor Routing (from the IPC, > but the MIL-STD has very similar wording): > > "The length of a conductor between any two lands > should be held to a minimum." > > You would be really stretching things to get my "no tees" rule from > that section. > > Question: Am I really losing it (entirely possible), or is/was there > such a rule, and if so, where is it and under what circumstances is/was > it invoked? > > Thanks, > > -Chris Lott > > -- > > ************************************************************************ > R. Christopher Lott, P.E. [log in to unmask] > Huntsville, Alabama > ************************************************************************ > > ################################################################ > 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 ################################################################