Hi Ingemar! Good input! The LCC photo illustrates a worst case scenario and there are many applications where LCCs are being successfully used. The main issue is that many designers unknowingly or ignorantly just use an LCC for a design without understanding the implications of having a ceramic component on a laminate pwb in terms of CTE mismatch. The physics are pretty straightforward - a large CTE mismatch results in solder joint damage. Using a plastic component (instead of ceramic), utilizing a controlled laminate material (as other TechNetee's have suggested), or evaluating the use environment impact (-55C to +125C vs -20C to 80C) are other mitigating factors in successfully implementing LCCs. Rockwell Collins has a number of successful applications of LCCs but with the multitude of plastic component availability have chosen to eliminate having to deal with the CTE mismatch issues associated with the LCC component style. I'll bet the number of times that Werner or Guenter have had to explain the implications of large CTE mismatch and LCC components to designers is larger than would be expected. Dave "Ingemar Hernefjord (KC/EMW)" To: [log in to unmask] <ingemar.hernefjord@ER cc: ICSSON.COM> Subject: [TN] LCC curiosa Sent by: TechNet <[log in to unmask]> 10/21/2004 04:59 AM Please respond to TechNet E-Mail Forum; Please respond to "Ingemar Hernefjord (KC/EMW)" Hi Steve! Wow, ya never would have thought a simple picture of a very beat up LCC would be so interesting! Dave Hi Dave, happened to get old article from APL on desk 'Reflow attachment and reliability testing of ceramic chip carriers'. And another from Bell Labs. According to these, the packages were not so bad (at that time). Quoted: 'The general implications are that minor cracking occurs in the solder joints during tempcycling, but to date no adverse effects have been seen..... ...........from the study it appears that chip carriers provide a highly reliable, easily testable, and easy to assemble packaging technique....' '...the solder joints withstood 1,000 cycles -40/+130 Centigrades and aging at as high as +175 Centigrades.........the failure rate at +80 C is projected to be negligible for fifty years....' Myself, was involved in development of a computer, whereas each board had some 100 LLCCs, built on multiceramic and copper technology. Think I have some pics still from that interesting time about 20 years ago... Ingemar Hernefjord Ericsson Microwave Systems --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------