Hi Joe - John Maxwell beat me to it but the process of soldering a wire to 
a surface mount chip capacitor must be done with significant due 
diligence. The ceramic body of the capacitor has very poor thermal 
exposure robustness and there is a high potential for causing the 
capacitor to crack. Here is a link to John's paper "Cracks - The Hidden 
Defects" which we give to our new process engineers so they understand how 
not to damage surface mount capacitors.

http://www.avx.com/docs/techinfo/cracks.pdf

Dave Hillman
Rockwell Collins
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Joe Macko <[log in to unmask]> 
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[TN] jumper wire attachment to top of chip component?






All,

 

A question came up about IPC-A-610 acceptability and the feasibility of
soldering a short piece of 32 awg jumper wire to the "top" of a 0402
chip capacitor due to space limitations that I would like to hear input
on and the technical risks. Normally, such jumper wires are positioned
parallel to the longest dimension of the solder land and soldered as
recommended by IPC but in this  case there is very limited space so it
is proposed that the wire be soldered on "top" of the component.

 

IPC-A-610E, 8.6.1.1 Jumper Wires, SMT - Chip and Cylindrical End Cap
Components states that that this is a " Defect - Class 1, 2, 3: Wire
soldered on top of chip component termination".

 

I look forward to hearing back from the hands-on experts.  thx

 

Regards,

-Joe

 

 


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