Screaming Circuits: CAD Parts Libraries

PROTOTYPE AND SMALL VOLUME
PCB ASSEMBLY MADE EASY

QFN Solder Paste Layer

I've got the fab order placed with Sunstone.com for my next demo project. The little board is represented here at pretty close to actual size on screen - provided you have a 22" monitor set at 1680 pixel horizontal resolution.... Read more

QFN Stencil Gerber

In the previous epside, Wally’s attack on Dilbert’s kingdom prompts Ratbert to perfect an “N”-Ray, to be discharged from a powerful Nullitrion, to neutralize and render useless Wally’s power plant. Dilbert tells Dogbert the Nullitrion can best be directed against... Read more

QFN Custom Stencil Layer in Eagle

It's been said over and over that you don't want to leave the solder paste opening wide open for a QFN center pad. 50 - 75% paste coverage will get you bets results. With full coverage, your QFN can end... Read more

BGA pads with Vias

No. This isn't a closeup of an owl face. There is still some debate on how best to create a land pattern for a 0.4mm pitch BGA. We recommend soldermask defined pads at that pitch. But that's not really what... Read more

Speaking of Small Packages...

T'was a a dark and stormy night when the news came through. Joe Layout had been both dreading and preparing for years. But it had always been little more than rhumors from a far off land. It was a looming... Read more

And Another Footprint Thing

When you are creating a footprint in your favorite CAD program, or reusing someone else's footprint, double check the zero orientation. This post discusses the IPC-7351 specified zero rotation orientation. This picture on the left shows a library component with... Read more

How to Build a footprint

Well, not really how to build one in a technical sense, but some thoughts on how to better ensure that you get it right. In theory, it shouldn't be that difficult. You download the datasheet and build the land pattern... Read more

Package Variants

Here's another issue we see from time to time involving the old, familiar, 0.1" pitch headers. When initially laying out the board, the footprint for the break-away header is used. It's small and easy to use. The headers are cheap... Read more

Day two. Custom parts

Moving on from where I left off a few days ago... I was planning on using the PIC18F2320, but in poking around, I found that the PIC18F2321 is about $3.00 less expensive in small quantities. I'm not entirely sure why.... Read more

Centroid / XYRLS / Pick and Place

Call it what you may, but surface mount assembly robots need this magic file to determine where to place your components and how to orient them. We call it a Centroid. Others may call it something else, but it's all... Read more