Amen to that. Xlinx is a good example of that. There are recommended patterns for qfps that are smaller than the physical part in some of their data books. Neil D.. At 08:45 AM 7/30/98 -0700, Matthew Park wrote: >Mark/Lisa, > >I think not, component manufacturers are good at making >components and not so for recommending land patterns for their >components. They don't count in everything that goes on to >solder a simple SMT comp from the begining to the end. > >When designing land patterns, Some of things you should >consider: >- component tolerance >- board fabrication tolerance >- pick/place accuracy >- which end of component pin/lead the formation of solder fillet > ocurrs >- amount of extra land area to set aside for robust solder fillet > formation and good wetting. > >By the time, all tolerances are added in, accuracy could be off as >much as 0.2mm. My recommendation is talk to your mfg >engineer. Professional SMT Component and Land Pattern Book >by SMT Plus is a good place to start, however my preference is >IPC-SM-782. Look into the last page of each IPC land pattern >section and the figure will explain tolerance and solder fillet req's > >regards >Matthew Park >SMT Manufacturing Engineer >NII - Norsat International Inc. > > > >>>> Lisa Anderson <[log in to unmask]> July 30, >1998 5:32 am >>> >Mark, > >Try an inquiry to the manufacturer. In most cases they have a >suggested land pattern to use for the >product on the specification sheet. > >Lisa Anderson >Paradyne Corp >Largo FL > >Mark Ross wrote: > >> We just bought the land pattern standard, IPC-SM-782 and >found that many >> of the components we are planning to design are not in here >and appear >> (?) to be unregistered. >> >> For instance SOT23-5 is not in the book. Can anyone >recommend a good >> source for ALL or most land patterns. A source that has a >proven land >> pattern track record? >> >> I do not want to use the IPC calculator and waste my time on >many >> patterns. I would like a good resource for this information. Or >does >> one not exist yet? >> >> Do I understand the process correctly that first a component >must be >> registered with JEDEC and then at some point somehow an >IPC land pattern >> for the component is established? >> >> We do not want to design surface mount products that fail >because of >> poor land pattern definition. Thanks in advance. >> >> Mark Ross >> Senior Design Engineer >> Whistler Auto-Mation Products. >> >> >################################################################ >> 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 >################################################################ > ################################################################ 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 ################################################################