The FREE IPC-7351B LP Calculator is a fantastic time saver. It is a land pattern calculator based on the IPC-7351B SMT land pattern standard that allows you to define your own CAD land patterns and offers seamless compatibility with the freely-distributed library documentation.
Ralph from the forums writes..
The Institute of Printed Circuits (IPC) has standards for “land patterns” (as they call pad shapes). You can download a free calculator from pcbmatrix.com that lets you generate IPC standard land patterns for any component. It still seems ridiculous, though, that every designer has to reinvent this wheel. There should have been a standard symbol and footprint file format invented a long time ago, with every component manufacturer providing downloadable libraries for their parts. You can download SPICE models from manufacturers, but have to do everything else yourself, or pay big $$$ for quality commercial libraries.

Printable catalog (PDF)

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Do you know how to actually get those ‘land patterns’ out of LP Calculator and into a form I can use? They seem to require you to buy their LP Wizard product to do that.
Comment by pelrun — November 16, 2009 @ 4:57 am
Pelrun: That’s the catch. It’s a great reference tool, but it’s only a ‘reference’ tool unless you fork over a pretty hefty wad of cash to be able to export anything.
Comment by Kevin Townsend — November 16, 2009 @ 6:15 am
That isn’t as useful as it could have been.
You can see what dimensions the calculator generates for land patterns and copy them manually into your Eagle parts, or use them in your text files that generate parts. No more guessing on SMT pad sizes, etc.
Their free calculator plus a little bit of scripting to replace their wizard, and we could have what we need, just not as automated.
Comment by SiliconFarmer — November 17, 2009 @ 12:17 am