Seems to me from vibration and drop shock testing, that LGAs are less likely to fail than BGAs. I know that BGAs in the current NASA/DoD round robin test were the first components to fail, but there were no comparable LGAs of the same size or I/O. Could it be the smaller mass because of the weight of the solder balls, or could it be less standoff from the board makes the LGA "stronger"? Any studies of the same device in BGA versus LGA through harsh environment - drop shock or vibration? Denny Fritz SAIC, Inc. -----Original Message----- From: Stadem, Richard D. <[log in to unmask]> To: TechNet <[log in to unmask]> Sent: Tue, Apr 19, 2011 12:42 pm Subject: Re: [TN] LGA geometry advice LGAs are actually very trouble-free, but there are certain steps in the process hat need to be done to make them that way. -----Original Message----- rom: TechNet [mailto:[log in to unmask]] On Behalf Of Jerry Dengler ent: Tuesday, April 19, 2011 10:52 AM o: [log in to unmask] ubject: Re: [TN] LGA geometry advice Eric, I would like to comment on the choice of LGA's. These devices usually cause an ndue amount of trouble to manufacturing. They are easily 3 times the trouble f a BGA. I would rather do a .5 mm pitch BGA than a 1.0mm pitch LGA. Regards, Jerry Dengler roduction Manager ergamon Corporation 80 Crooked Lane, Unit# 3 ing of Prussia, PA 19406-2567 .S.A. 610) 239-0721 Phone 610) 239-0720 Fax -----Original Message----- rom: TechNet [mailto:[log in to unmask]] On Behalf Of Eric Christison ent: Tuesday, April 19, 2011 11:36 AM o: [log in to unmask] ubject: [TN] LGA geometry advice Rights folks! I'm designing a new surface mount device which originally started off as X 5 square. It has 25 I/Os. It's LGA is a 5 X 5 array of 0.60 diameter pads on a 1 X 1 pitch. The device has now increased in size to 7.5 X 7.5. Now, do I increase the LGA spacing to cover the increased area again or o I stay with what fitted on the 5 X 5 device? I'm inclined to stick ith the original LGA as I believe that the stress analysis will tell me hat the smaller grid will have lower stresses in the SJs than the igger grid. Are there any practical reasons for maximising grid size? Regards, -- ric Christison onsumer& Micro group maging Division STMicroelectronics (R&D) Ltd 3 Pinkhill dinburgh EH12 7BF nited Kingdom Tel: +44 (0)131 336 6165 ax: + 44 (0)131 336 6001 The contents of the email are ST confidential. _____________________________________________________________________ his email has been scanned by the MessageLabs Email Security System. or more information please contact helpdesk at x2960 or [log in to unmask] _____________________________________________________________________ --------------------------------------------------- echnet Mail List provided as a service by IPC using LISTSERV 16.0 o unsubscribe, send a message to [log in to unmask] with following text in he BODY (NOT the subject field): SIGNOFF Technet o temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) o receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest earch the archives of previous posts at: http://listserv.ipc.org/archives or additional information, or contact Keach Sasamori at [log in to unmask] or 47-615-7100 ext.2815 ---------------------------------------------------- ______________________________________________________________________ his email has been scanned by the MessageLabs Email Security System. or more information please contact helpdesk at x2960 or [log in to unmask] _____________________________________________________________________ --------------------------------------------------- echnet Mail List provided as a service by IPC using LISTSERV 16.0 o unsubscribe, send a message to [log in to unmask] with following text in he BODY (NOT the subject field): SIGNOFF Technet o temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) o receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest earch the archives of previous posts at: http://listserv.ipc.org/archives or additional information, or contact Keach Sasamori at [log in to unmask] or 47-615-7100 ext.2815 ---------------------------------------------------- ______________________________________________________________________ his email has been scanned by the MessageLabs Email Security System. or more information please contact helpdesk at x2960 or [log in to unmask] _____________________________________________________________________ --------------------------------------------------- echnet Mail List provided as a service by IPC using LISTSERV 16.0 o unsubscribe, send a message to [log in to unmask] with following text in he BODY (NOT the subject field): SIGNOFF Technet o temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) o receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest earch the archives of previous posts at: http://listserv.ipc.org/archives or additional information, or contact Keach Sasamori at [log in to unmask] or 47-615-7100 ext.2815 ---------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 16.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------