Does anyone have any information concerning mounting LCCC (Leadless ceramic chip carrier) on FR4 PWBs? I know it is not a recommended practice since the CTE of the two materials is mismatched. However we have some designs in which the parts are only available in LCCC's or designs have already been fabricated. The operating environment is mild, 0 - 45 C. Thermal cycling will be less than 1000 cycles. Number of units built, < 20 units. Component lead count, 40, 28, and 20. Component area 0.5 x 0.5 inches and 0.36 x 0.36 inches. At what temperature is the CTE mismatch a problem? Do any vendors sell preformed leads which can be added to the LCCC? Are there special solders which will tolerate more stress? Any help is appreciated. Tom Obarski Harris Corp ################################################################ 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 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 ################################################################