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solder paste alloy effect on high frequency board

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#52008

solder paste alloy effect on high frequency board | 10 October, 2007

hi we use a no clean solder paste with the sn63pb37 alloy and our high frquency board doesn`t have any problem in test but after this product is finished now we use 2 different solder pastes 1. sn62 pb36 Ag.4 RA tape 2. NC type lead free with Ag in the alloy and now our high frequeny board doesn't pass the test. don't you think that it might be of the Ag that is composed in the alloy ?

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RDR

#52020

solder paste alloy effect on high frequency board | 10 October, 2007

everything else EXACTLY the same? meaning exact same product number from the same manufacturer same fluxes used in the paste? no additional no clean "touchup" or hand soldering operations?

No expert by any means but it would seem odd to me that the 2% silver would cause this type of issue.

Russ

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#52021

solder paste alloy effect on high frequency board | 10 October, 2007

Does it fail to function or does it function outside of acceptable tolerances?

If the latter I wouldn't know what to think, but if the former I would feel obligated to suspect solder quality or maybe even a component problem with the elevated lead-free temperatures.

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#52025

solder paste alloy effect on high frequency board | 10 October, 2007

I have always understood that on boards (or circuits) operating over 900 MHz, No Clean fluxes are to be avoided. Apparently the residues left behind, while non-conductive and non-corrosive, will change impedence of the circuit. It may be a possibility that the change in paste also incorporated a change in flux agent, which has induced changes in how the circuit is working.

Good Luck!

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#52032

solder paste alloy effect on high frequency board | 11 October, 2007

Lots of papers out there on HiFreq circuits and the effects of solder paste residue. Google Dr. Karen Tellefsen. Simple test...take a "failed" board, remove the residues, test again. Has the problem gone away?

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#52293

solder paste alloy effect on high frequency board | 4 November, 2007

can you send me the articles about the high frequency boards issues with different types of solder paste alloy because i can`t find any free document about this article

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#52324

solder paste alloy effect on high frequency board | 5 November, 2007

"Effects of surface finish on high frequency signal loss using various substrate materials" - Call Don Cullen at Mac Dermid or Larry Gatewood at Rockwell Collins for a copy.

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