I've been using QFP packaged ATxmegas up to now but my latest project is highly space sensitive, so I need to use the QFN parts. These packages are fairly new and reliable soldering requires the footprint design to be absolutelt correct, not just have rectangles of copper in roughly the right place.
Atmel unhelpfully says the following: "We do unfortunately not supply CAD symbols/PCB footprints. All AVR devices uses a standard industry package (JEDEC). The formal reference to the standard is in the respective datasheet under the 'Packaging Information' chapter".
They go on to recommend, "There are footprints available made by third party vendors. For example, you can use the link: IPC Land Pattern Calculator for calculating land patterns using the IPC-7351A Land Pattern Calculator. It allows users to view IPC approved land pattern dimensional data in tabular form as well as graphical images that illustrate how a component is attached to the land pattern on the board".
Unfortunately, IPC-7351A has been superceded by IPC-7351B, and the link provided gives no land pattern calculator. However IPC has lost no opportunity to make a buck, offering the calculator free with the purchase of the full standard document for $136!
Now I don't want to purchase IPC-7351B, I don't want to spend $136, I just want to use the Atmel parts I'm about to pay for.
Does anyone have a reference to reliable QFN footprints for Atmel devices? Specifically I need footprints for the 44-pin ATxmega128A4U-MH and the 64-pin ATxmega128A3U-MH.