Leonard, I am not aware of any guideline placing via holes in smt lands except micro-via applications. Any board guideline will tell you "no via hole in smt land" Period! Some of Ghz desingers drives me nuts over this. But I am in the process of designing and testing via holes in smt lands. I likely will use 0.38 or 0.50mm via holes located on under chip component (off-centered) and will tent solder side via holes to prevent solder wicking down thru them. I know most board vendors can do 0.38mm holes with no cost increase. regards Matthew NII >>> Leonard Toohey <[log in to unmask]> February 16, 1998 2:10 pm >>> What is the state of the industry regarding putting vias in the center of SMT discrete device pads? I am mainly wanting to know about 0603, 0805 and 1206 devices. Is board thickness a factor? What about via hole size? Thanks, Leonard Toohey [log in to unmask] 12303 Technology Blvd. Austin, TX 78727 Ph(512) 257-5423 Fx(512) 249-7236 http://www.netspeed.com ################################################################ DesignerCouncil 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 DesignerCouncil <your full name> To unsubscribe: SIGNOFF DesignerCouncil ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################ ################################################################ DesignerCouncil 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 DesignerCouncil <your full name> To unsubscribe: SIGNOFF DesignerCouncil ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################