Hi Ken. Motorola has done extensive studies picking up where IBM left off. I strongly recommend that you contact your local Mot distributer and get Mot's BGA PCB packaging/layout design guidelines. They claim that on a PBGA (plastic) one should use a soldermask defined pad. That would be a soldermask opening smaller than the actual pad diameter. On a .050 pitch grid array, for example, they state to use ONLY a .023 opening on a pad of approximatley .030. For ceramics and columns it's a diferent configuration completely. But - get the specs from Motarola. They appear to have the answers based on extensive studies they've done. Regards, Russ Steiner Controls/inc. Good luck/best wishes. -----Original Message----- From: Ken Patel <[log in to unmask]> To: [log in to unmask] <[log in to unmask]> Date: Tuesday, October 27, 1998 3:04 PM Subject: [TN] Hot: Trace width and air gap for 1mm pitch BGA >BGA Design/process Guru, >We are designing board with 1mm (39.37 mils) pitch 672 pin BGA. I have the >following questions which I need urgently. > >(1) What is the recommended pad size? >(2) What the recommended via size? >(3) What will be the trace width and air gap if I need to pass 2 traces? We >are limited in number layers so we want to go for double traces instead of >single trace between the pads. > >re, >Ken Patel >______________________________________________________ >Ken Patel Phone: (408) 490-6804 >1708 McCarthy Blvd. Fax: (408) 490-6859 >Milpitas, CA 95035 Beeper: (888) 769-1808 > >################################################################ >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 ################################################################