Screaming Circuits: December 2006


Proto Via in pad

While we don't like it, with some designs, if done properly, there can be a number of compelling reasons for putting vias directly in the SMT pads for BGA and QFN packaged components. It can make routing easier with big... Read more

BGA coming loose?

Have you had BGAs with some or all of the solder balls connecting poorly or not connecting at all? If you use an ENIG (Electroless Nickel Immersion Gold) board finish, this may be due to the infamous "black pad" syndrome.... Read more

More than just chips

I ran across a rather inspirational story on Guy Kawasaki's blog about a small business based in Kabul, Afghanistan. It's not an electronics business. They make soccer balls. Still, the posting, "Ten Questions With Aziza Mohmmand" gives a clear view... Read more

BGA layout

The first plastic BGA (Ball Grid Array) was invented by Motorola and Citizen in 1989. Today, BGA packages are part of many Design Engineers parts library. Below are some links to learn about using BGAs in your next PCB design.... Read more

New survey

We've put up a new survey. It's just two pages about the sorts of things you deal with when trying to get a prototype assembled. Spend a moment and give us your thoughts to help us serve you better. Duane... Read more

Custom CAD parts libraries

Back to Mark Rules and the mini control board again. He's using Eagle CAD which comes with good and not so good. The good is that Eagle is pretty powerful, yet inexpensive and easy to learn and use. The no... Read more

QFN solder voids

I've written a couple of posts about QFN float problems (here), (here) and (here). There is another problem we run across as well. With larger QFN parts, the opposite problem can occur in the center pad area. When the square... Read more

Digi-Key part numbers

In my post yesterday about the Mark Rules project, I mentioned Digi-Key part numbers. Every now and then someone will ask us if we accept Digi-Key part numbers in the Bill-of-materials (BOM). The answer is a resounding yes. We love... Read more

BGA Via in pad

We're starting to see more an more .5mm ball pitch mid-count BGAs here at Screaming Circuits. When you've got 400 - 500 balls on a .5mm pitch BGA, routing becomes a real challenge. One of the solution designers are exploring... Read more

SMT Connectors

When we last left Mark Rules, he had made most of the component decisions for his miniature microcontroller and motor driver board. He still hadn't made a final call on the exact PIC processor. All of the options fit the... Read more

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