Close Only Counts …

I think this one has both some land pattern issues and some schematic issues. It’s unfortunately pretty common to see footprints that are close, but not close enough to work. Looking at the data sheet here, there may be a schematic issue as well. The only connections on to the part on this board are ground and P3. I don’t know the part, so I suppose it’s possible that all it needs is P3 and ground, but it looks more like a case of the footprint being wrong and the pin connections being wrong. Pins 1, 2, 3, 5 and 7 are all ground, but on the board, 1 and 3 go some place else. Bummer.

Making custom CAD parts can be pretty annoying and it seems to be a function disproportionately prone to error. Why is that?

Duane Benson
in horse shoes, hand grenades and sometimes atom bombs

http://blog.screamingcircuits.com/

1 thought on “Close Only Counts …

  1. not enough info… to comment on the example(s)
    pictures too small..
    function/name of IC not included (analog vs digital grounds?)

    Don’t have much of an issue with getting good pcb layout artwork on most components…
    but that could be due to a number of things…

    With older CAD systems , less experience with production issues, poor creation processes … your observation is “spot on”
    Library generation….disproportionately prone to error.

    My biggest current issue: so many variations on the specs…. for the pins on connector systems and sub-assemblies.
    top view vs bottom view not clearly identified.
    pin 1 in numerous physical locations. (not consistent with a given outline)

    standards … gotta love em!… that is why we have soo many!

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