Screaming Circuits: Via in Pad

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PCB ASSEMBLY MADE EASY

Random Via-In-Pad Myth #5

Myth #5: When you need thermal vias, more is better, bigger is better Hmmm. Logically, this would seem to be the case. There are limits though; especially if you want a reliably assembled product. Older parts with heat slugs easily... Read more

Nightmare on BGA Street

I seem to be in a bit of a BGA mood lately. I do that sometimes - pick a subject and talk it to death before moving on. Well, maybe not quite talk it to death, but at least talk... Read more

BGA Woes

Quite a few of the new chips I see coming out stick to the BGA or QFN form-factor. Sometimes they'll be referred to as WSP (wafer scale package) or CSP (chip scale package), but those are still just little BGAs.... Read more

A Bit More On the LGA

After my last post about LGA land patterns, I received a couple of questions asking for more detail in a few areas. "The LinearTech LGA apnote (LTM46xx series) shows planes on the mounting layer interconnecting pads that are solder mask... Read more

Hand To Machine

It's getting very difficult to hand solder many parts these days. Some people give it a try, but in general, if you're dealing with the really tiny parts or leadless parts, it's just not possible, or at least not practical.... Read more

Via Caps

The best way of dealing with via-in-pad requirements is to have the vias filled and plated over at the board house. There can still be some issues with that technique, but if done right, is very reliable and the best... Read more

Little Chippy Challenges

And in terms of "Chippy", in this context, I'm referring to chip-caps and any other tiny little two-connector components. When considering surface mount, most people think of the many-connector parts, like BGAs and QFNs as the challenging components. That's mostly... Read more

PCB Planarity, Not Polarity

Via-in-pad can ruin a manufacturer's whole day. Or, if properly done, can go completely unnoticed. There are a number of ways to properly put a via in a pad but the best is to have it filled and plated o... Read more

Random Via-in-Pad Myth #7

Myth #7: In regards to via-in-pad, all PCB finishes are the same Well, it might seem so, but let's look a little closer. No. Not that close. Back the camera up a bit. Here's a good example: In some cases,... Read more

Random Via-in-Pad Myth #3

Myth #3: It’s okay to put vias in BGA pads because the extra solder (the solder ball) on a BGA will prevent any problems Here's an example of a via in pad situation we don't like; A large number of... Read more