Screaming Circuits: QFN and DFN

PROTOTYPE AND SMALL VOLUME
PCB ASSEMBLY MADE EASY

AT Tiny is Tiny

I just spotted a note on Twitter, from SiliconFarmer, referring to the ATtiny44A coming in a 0.45 mm pitch QFN as well as a 0.5mm pitch MLF package. (In practice, an MLF is the same as a QFN, by the... Read more

Funky QFN Land Patterns

I've described the optimal way to create your land and solder paste layer for QFNs a couple of times before. But that was for a standard square QFN or rectangular DFN. What happens if you look at the bottom of... Read more

Re-runs

I've been pretty occupied with the upcoming Embedded Systems Conference in Boston. The exhibition is next week on Tuesday, the 21st and Wednesday the 22nd. Screaming Circuits will be in booth 809. Stop by if you happen to be at... Read more

Easy Reading for a Long Weekend

The holiday is upon us and most folks here in the US will have a three day weekend. Of course, when you're an engineer on deadline, all too often holidays don't really mean that much. Here's a little food for... Read more

All Leadless

It wasn't too terribly long ago that just about any design could still be built all thru-hole. Okay, maybe it was a little longer ago than that. Once the big CPU chips stopped showing up in PGA (pin grid array),... Read more

Large Via In Pad

I haven't written about via in pad in a while, but the issue hasn't quite gone away yet. This particular QFN, to the left, has the vias tented, which is good. However, it could be better. If you look close,... Read more

Many Faces of the QFN

When I first started using a CAD package for circuit design, I couldn't understand why the software didn't come with all of the standard footprints and why that wouldn't be good enough. That level of ignorance was hopefully pretty short-lived.... Read more

Inverted QFN Land Pattern

Have you ever experienced the heartbreak of inverted land pattern? It's not supposed to happen, but every now and then, it does. Maybe something happened when creating a custom footprint. Maybe, somehow it got inverted in the CAD software and... Read more

What's Wrong With This Picture?

What's wrong with this picture? I forgot to warn you that there'd be a pop-quiz. It's only worth 10% of your final grade though, so not to worry. We're fully into the rainy season here in Oregon now. It's dumping... Read more

Tented QFN/QFP Via in pad

Here's a pretty decent example of mask-tented vias in the thermal pad of a QFP. Most manufacturers recommend no more then 100 - 125 um wider than the via to minimize voiding and thermal insulation in cases like this. This... Read more