Khaled asked why neckdown. Just meaning that if you are trying to connect a massive trace like .3 .4 or .5 wide to a .062 pad on a chip (thereby having solid copper all around the pad), (I realize a trace of this size would not be able to connect to center of pad without shorting to the one next to it, but my point is that if there is solid copper on at least 3 sides of the pad) and you want to have a good solder joint, you may want to provide some thermal relief either by creating a positive thermal connection to the pad if cad software will do this or necking down the trace close to the pad to kind-of create a thermal relief for the pad. Hope this was clear enough just in words. Robert M. Wolfe -----Original Message----- From: Khaled H. Fouad [SMTP:[log in to unmask]] Sent: Thursday, November 12, 1998 6:35 PM To: [log in to unmask] Subject: Re: [TN] neckdown "Wolfe, Robert" wrote: > > Neckdown is a term used when a trace needs to be less wide in an area to get > through pad/lands or just for pad entry because of solderability issues. > I.E. say a conductor trace on a board is being routed at .025 wide and you > need to get between two pads that have a .020 clearance between them you > will need to neckdown the trace to say .008 wide. Or you are entering a .062 > pad with .10 trace and need to neckdown to say .040 close to the pad for > solderability. Longwinded but basically making a trace less wide for a short > distance to maintain design rule clearance or solderability. > Robert M. Wolfe > Hi Robert Why do you need to neckdown a trace when you enter a pad. Is this a DFA vaiolation,plz explain ? -- Best Regards Khaled H. Fouad ---------------------------------------------------------------------- Senior PCB Designer Research & Development Department International Electrical Products Member of BAHGAT Group Second Industrial Zone, Plot 240 6 October City, Egypt Tel. : +20 (11) 333414-9 Ext. : 312 Fax. : +20 (11) 335613 (Direct) +20 (11) 333420 WWW : http://www.bahgat.com Email: [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 ################################################################