Ha! I just got a copy and have read up to page 33, right before Appendix A. Now I know I will be reading tonight. :}
Bev
--------------------------
Sent from my BlackBerry Wireless Handheld (www.BlackBerry.net)
-----Original Message-----
From: Guy Ramsey <[log in to unmask]>
To: 'TechNet E-Mail Forum.' <[log in to unmask]>; Bev Christian <[log in to unmask]>
Sent: Thu Mar 20 14:28:19 2003
Subject: RE: [TN] SMT Component Standoffs
Yes, now you are getting picky ;~) Do you have a copy of IPC-D-279?
Section 3.5 Solder Joint Reliability, specifically 3.5.1.3 Solder Joint
Height seems to be the variable you are asking about. It is part of the
prediction equations A-3 and A-4 in the Design Guidelines. I have not
seen these translated into DFR rules. I think the other variables you
mentioned would exert too much of an influence to make any hard and fast
rules. Flexible rules . . . Sounds like Philadelphia traffic laws.
Werner?
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian
> Sent: Thursday, March 20, 2003 1:31 PM
> To: [log in to unmask]
> Subject: Re: [TN] SMT Component Standoffs
>
>
> Thanks, Guy, BUT this has to do with cleaning rather than
> mechanical reliability.
> Bev
> --------------------------
> Sent from my BlackBerry Wireless Handheld (www.BlackBerry.net)
>
>
> -----Original Message-----
> From: Guy Ramsey <[log in to unmask]>
> To: 'TechNet E-Mail Forum.' <[log in to unmask]>; Bev Christian
> <[log in to unmask]>
> Sent: Thu Mar 20 13:17:55 2003
> Subject: RE: [TN] SMT Component Standoffs
>
>
> There is help in IPC-SM-782A section 3.6.1.7 Component Stand
> Off Height for Cleaning and the associated table 3-7. The
> stand off recommendation varies with the component size. For
> example small component < 3mm x 3mm stand off > 0.05 mm. A
> large component 50mm x 50 mm stand off > 0.5 mm.
>
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian
> > Sent: Thursday, March 20, 2003 12:56 PM
> > To: [log in to unmask]
> > Subject: [TN] SMT Component Standoffs
> >
> >
> > TechNetters,
> > When I was at a former employer there was a minimum stand off
> > in the company specs. I have forgotten what that was. Now I
> > know that it can/should be different based on the solder, use
> > environment, pad sizes and lead/termination materials, but I
> > was wondering if anyone would be willing to share what they
> > have on the subject. I am particularly interested in land
> > grid array devices, if I may be so bold as to be picky. :)
> > Thanks in advance.
> > Bev Christian
> > Research in Motion
> >
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