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Re: A few extra component footprins


>>>> I've looked at some of the datasheets above, and I think the datasheet
>>>> http://pdfserv.maxim-ic.com/package_dwgs/21-0137.PDF is wrong
>>>> - the difference between the variants seems to be the size of
>>>> the exposed pad (D2,E2), but 21-0137.PDF lists them as identical.
> I'm not sure what you mean.
> http://pdfserv.maxim-ic.com/package_dwgs/21-0137.PDF lists the size of
> the exposed pad as identical for variations of the same N. For N=14 D2
> is 1.7mm instead of 1.5mm.
>> Well, that's what I meant - 21-0137.PDF lists _all_ dimensions for
>> the "same N variations" as identical, which doesn't make sense.
>> The other datasheets on maxim-ic.com
>> lists varying sizes for the thermal pad.

Oh, I see what you're confused about. there are indeed several
variations of the package, but they all fit on the same land pattern.
Who cares if the footprint pad is larger than the pad on the package? It
won't interfere with the soldering process. This makes life easier for
us since we only need one footprint, and considering the 3D Viewer in
kicad is more of a convenience than a CAD feature, it's safe to only use
one 3D package per N, perhaps the one with the larger pad.

>>>>> I think there are also larger packages as well;
>>>> Yes, much larger - up to 56 "pins" :-)
> AFAIK, TDFN only goes to 14 pins. TQFN on the other hand, does go to 56.
> I think you're referring to TQFN. I'll look over the .dim and see if I
> can get some dimensions in (If I can't then I should probably try to fly
> to save the world from an idiot mind :p ).
>> You're right - I overlooked the TDFN vs.
>> TQFN when searching for the max size :-(
Still, the varying packages sizes for TDFN8, for example, might be a bit
of a headache. Perhaps we should adopt a naming of
TDFN8-M065-3X3, TDFN8-M065-3X2, etc...

>> Ref 5 looks interesting, but www.uspro.com times out :-(

>>>> I haven't understood what all the numbers and fields means yet, but
>>>> as freecad can read IGES (*), the freecad source should also contain
>>>> some useful info for writing a script to convert IGES to VRML.
>>>> (*): Well, sort of - freecad is definitely alpha code:
>>>> I've tried feeding the simple example on the Wiki to freecad,
>>>> and it gets the coloring wrong - the points, arcs and lines
>>>> should be yellow, red and green, but they're all shown in black.
>>>> Also, Wiki Ref 6: http://www.wiz-worx.com/iges5x/wysiwyg/f214x.shtml
>>>> is totally wrong (most of it is missing).
>>>> Fortunately, the missing stuff is 2D graphics, and the Molex
>>>> connectors shows up just fine (except for the coloring).
> Hmm, I just noticed that IGES contains color information. If it's any
> consolation, not even Inventor can get the color right (well, except for
> the yellow lines).
>> I found an open source (Java) IGES viewer on
>> http://ts.nist.gov/standards/iges/,
>> but unfortunately, it's 2D only.
>> It does get the colors right, though, so I'll
>> take a look at the source when I get the time.

This page has some interesting "things":

"This release of WISLjr™, the freeware (Lite) version of the WiZ WORX
IGES Source Library, requires the libplot function library included with
the GNU Plotting Utilities"

And I would also like to point out and emphasize:

"will feature libiges-1.0 [..], and hopefully destined to become the GNU
standard for importing IGES files"

I can't see any download link, so I have no idea what they really mean
by that.

>> IGES contains a lot of advanced features, such as
>> spline curves and surfaces, so how easy it is to translate
>> an IGES file to VRML depends on which features are used.
>>>> As KiCad only understands VRML IndexedFaceSet and materials,
>>>> any 1D and 2D info (points, lines, arcs, etc.) in an IGES
>>>> file will get lost - only the 3D faces can be converted.
>>>> However, that should be enough for kicad, I think.
> Yes, the 3D faces are all that's needed in kicad. I'm not sure how the
> pieces are supposed to be colored; Inventor displays the body and pins
> as one piece, in one color.
> Worst case scenario, there's also the possibility of converting PRO/E or
> STEP files, as molex provides all three variations (though I think STEP
> is binary).
>> ... or create the 3D view ourselves from perl :-)
Have you seen how complex the pieces are? Ok, just kidding, some
capacitors in your library are far more complex than that.

>> I don't know which will be easiest, as that depends on the
>> available info on the file formats - probably not much :-(

I thought that converting some faces from an *existing* model would be
the easiest route. If we end up generating the models from Perl, we
could include the metal piece in the middle of the hole, which, for some
reasom, Molex seems to have overlooked.

I say let's keep the focus on generating the footprints, those are the
heart of the matter. The 3D packages can be added after the footprints
are done. That is of course, if you have no preference on getting both
ready at the same time :).


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