Allen,
It is all about balance of forces caused by the solder cooling equally,
it is fine if the other pads match the quicker cooling rate, if the
imbalance is enough then the forces can cause tombstoneing or shifting.
Rodney 

-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of
Allen T. Maddox
Sent: Wednesday, July 27, 2005 2:47 PM
To: [log in to unmask]
Subject: [DC] Trace width ratio to pad

Hey Folks,
 
I was always told to NOT exit a pad, especially a SMT pad, with a trace
the same width of the pad for the reason of dissipating the heat off the
pad and creating soldering issues.
I have an engineer who doesn't believe me and wants proof. Does anyone
have any articles that support what I've been taught, or have I been
mislead all these years?
 
Thanks,
 
 
Allen Maddox C.I.D.
Sr. PC Board Designer
GAI-Tronics, Corp
610-796-5854
PO Box 1060
Reading, PA 19607-1060
 
[log in to unmask]
www.gai-tronics.com


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