That is a really good question, but I don't know how much response you will
get, because in my experience it is usually the opposite that happens. The
assembler wants to reduce the pad size and corresponding amount of solder
paste applied. I've never thought about how IPC says minimum, and how that
could be interpreted to mean that you should make everything bigger if you
can, because nobody does that! Everyone wants smaller smaller smaller
(except maybe big pads on through-hole for high-power components, or
something like that). So maybe you should take that "land sizes should be
maximized" statement with a grain of salt, since I believe the IPC
recommendations are already bigger than anyone else's out there. (correct me
if I'm wrong you guys, I'm just a lowly layout guy)



                -----Original Message-----
                From:   Mark Holmes [mailto:[log in to unmask]]
                Sent:   Friday, September 24, 1999 1:09 AM
                Subject:        Pad Sizes for good solder Joints


                All the data I have regarding pad sizes (e.g. IPC-2221
9.1.1) give examples
                on how to calculate Minimum pad sizes, usually from a PCB
fabrication
                standpoint. IPC-2221 states that all lands and annular ring
shall maximised
                wherever feasible, consistent with good design requirements
and electrical
                clearance requirements.

                My questions are: How do I determine the pad size that will
give me the best
                soldered joint?


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