Louis, Go to site www.rampinc.com, then to search and browse thru Free Paper Downloads. Here you can search for Palladium Plating. The list should be 2-3 papers. When you click, you will go to TI site for that paper. Print or browse. Good Luck. "Louis, Edwin @ CSE" wrote: > After some problems here with cracked solder joints on Alloy 42 leaded TSOP > devices, our stress analysis expert did some calcxulations And found that > the stress were above yield strength for the SN63 solder but not by much. We > sent some of the devices back to the manufacturer for their testing and they > found solder joint pull forces necessary to break the lead/solder bond to > be between 0.33 Kg and 0.78 Kg. The former is 0.726 lbs and the latter is > 1.716 lbs. We are talking about fine pitch 19 mil. > Some one in the assembly business said that between 1.0 and 1.5 lbs pull is > expected. These alloy 42 leads had a tin/lead (high lead composition) > plating which was not reflowed. My experience shows has been that tin/lead > plating has to be reflowed in order to be > a protective film. This type of plating is very porous and the lead oxidizes > easily. I hear reports from some quarters that alloy 42 > TSOPs are used successfully and others say never use alloy 42 TSOPs they > don't work. We encountered a manufacturer who used identical TSOPs as we > used but did not complain about any problems. The difference was that they > assembled the parts as soon as they arrived. We did not. Our solder joints > showed cracks at the heal hours after soldering. Reflow of our stressed > joints > manually, using RMA flux, alleviated the problem. I am thinking here that > the alloy 42 TSOP problem is caused partly by solderability > and partly by coefficient of expansion mismatch. I have heard that some > people are changing to palladium or palladium/silver > plating to overcome solderability problems. Can some one tell me where to > learn about these platings and are they worthwhile > pursuing. > > ############################################################## > TechNet Mail List 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://www.ipc.org/html/forum.htm) for additional > information. > If you need assistance - contact Keach Sasamori at [log in to unmask] or > 847-509-9700 ext.5315 > ############################################################## -- ____________________________________ Regards, Pratap Singh Tel./Fax: 512-255-6820, e-mail: [log in to unmask] or [log in to unmask] ############################################################## TechNet Mail List 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://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################