Eagle Tutorial – How to add a new package to a component @ The Adafruit Learning System. Ladyada writes -

There are thousands of devices in the ‘default’ library that comes with EagleCAD but whaddyaknow, the exact package/device you need isn’t always going to be one of those thousands. However, instead of making a brand new device from scratch every time you can often ‘merge’ two existing devices, or at least reuse the SMD package. Not only will you save time, but it can minimize mistakes. (Note I say itcan – be sure to always always triple check pinouts, package sizes, dimensions and more!)

This little tutorial will show you how to create a new package for an existing device. It’s not a beginner tutorial so you’ll have to learn how to use Eagle first, but its one of those skills that can save you tons of time.

The chip I’ll be looking to add today is this fine quad 2-input NAND Schmitt trigger. Specifically, I want to add the TSSOP package.

Learn more.