Electronic – What standards cover foot prints for standard part packages


So far I see some JEDEC standards for part packages, but I need standards for the corresponding footprints. For example MS-026 is a JEDEC standard for a PQFP part, so what would be the standards that covers the foot print for this part?

Just a note, I started looking for this after seeing a few datasheets' recommended layouts that were smaller than the pins on the part.

Best Answer

It's the IPC-7351B - "Generic Requirements for Surface Mount Design and Land Pattern Standard"

The document only provides recommendations; there is no enforcement. However, more and more manufacturers seem to be using it to inform their footprint suggestions.

Note that this spec isn't easy to use directly. Instead of tables of land pattern dimensions, you see sections like this (take from a previous version of the spec):


Instead, I use a software called Library Expert. It's free and quite useful. It creates footprints to the IPC-7351 spec. It will actually build up the symbols for a number of software packages, e.g. Eagle, OrCAD, Altium, and others.