Screaming Circuits: August 2007

Conan Visits Intel

This is a funny video of Conan O'Brien visiting the main Intel facility in Santa Clara, CA.  It's not quite the same as touring Screaming Circuits, but it's good for a laugh.  I could swear I saw Bill Lumberg in the cafeteria.

- Jered

Embedded Systems Conference

Mark your calendars people, because Screaming Circuits is taking over Boston! Metaphorically speaking, of course.


We will be attending the Embedded Systems Conference in Boston, MA on September 19th and 20th. If you happen to be in the Boston area or plan on coming out, register for a free exhibit pass here. We will be in booth 1131. It is near the back, next to the showcase of the new and innovative companies they call the “Disruption Zone.”

The show runs from 2:00pm to 7:00pm on Wednesday and 11:00am to 6:00pm on Thursday at the Hynes Convention Center. It’s a great event full of info about chips, processors, embedded software, embedded computers, and, of course, pcb assembly.

If you come by our booth, ask us about our show special! We will be giving away items with a priority code good for 10% off of labor on your next assembly order. This can be combined with our new customer 10% discount (if you are a new customer) giving you 20% off to try our services for the first time. We will also be giving away our newly designed t-shirts. However, with these awesome shirts we are more exclusive than inclusive. To find out how you can be one of our t-shirt wearing groupies, stop by our booth and ask. You will be glad you did.

We will also be featuring some cool projects from organizations that we're sponsoring for the 2007 - 2008 academic school year. The organizations are filled with really neat individuals, and we are thrilled to be working with them!

MicroCSP (Chip Scale Package) Parts

We received a question about a MicroCSP (also called flip-chip by some manufacturers or Wafer Level Package) packaged part the other day. If you're not familiar this type of package, it's a lot like a little BGA - a very little BGA. Basically, the solder balls are bonded right to the silicon die or a substrate layer on the die. That means that the entire part is the size of the silicon. Very small.

This particular part is an eight ball chip that is 1.8mm X 2.5mm and less then half a mm thick. The solder balls are in two rows at a .5mm pitch. It's a pretty impressive package. Interestingly, though, this isn't the smallest part or pitch we've placed. It's still bigger than an 0201 passive and we've placed a Texas Instruments 4 ball flip-chip that's a bit smaller than this as well. We've placed larger MicroBGAs with .4mm pitch also. Check out this Appnote from Analog Devices talking about one of their wafer level chip scale package parts.

Because there aren't any wire bonds and leads, this package can deliver improved electrical performance and, of course, you can put more of them on the board. Still, there are a lot of challenges with this type of part. If you are going to use one of these, make sure your board house can really register fine traces and solder mask.

NSMD (non solder mask defined) land pads are recommended and if possible don't route any traces between pads. If you need to put vias in the pads, the only reliable method is to fill and cap the via. If you do that, just be sure that the surface ends up totally flat. (there's always one more thing, isn't there?) Sometimes plugged and plated over vias end up slightly bulgy or with a slight dip. Either will lead to a less reliable connection.

We can assemble this type of part for you, but it would be best to give us a call and chat with one of our manufacturing engineers first.

Duane Benson
Tiny is as tiny does

Black Pad article in SMT Magazine

Black pad was a big problem a few years ago when ENIG (Electroless Nickel Immersion Gold) finish boards first started popping up. It's not so much of a problem these days, but we do still see it from time to time.

Sc_black_pad_illustration If you think you may be having black pad problems with you ENIG boards, or similar problems with immersion silver boards, Check out the article Screaming Circuits recently had published in SMT Magazine online.

Just note that down near the end of the fifth paragraph, I say that problems with the "tin" layer lead to black pad. It's really the nickel layer that causes the problems. I inadvertently said tin. One of our readers pointed that out to me. Oops.

Duane Benson
Don't look; Heisenberg may have been right...

Need help with Printed Circuit Assembly?

First, a question: Is "printed circuit assembly" a noun or a verb? Anyone... Anyone...

We tend to use the phrase "PCB assembly" more often than just "PCA" or "printed circuit assembly". Though, I have been told that "PCA" is a more appropriate noun used to describe our finished product. Regardless of what you call it, pcb assembly, or the printed circuit assembly process or prototype assembly; it's getting a lot more difficult.

I've been paging through a catalog from Practical Components - a manufacturer of dummy components, test boards and training aids. Page 17 shows a dual row MicroLeadFrame package (MLF and MicroLeadFrame are registered trademarks of Amkor Technology). It's basically a QFN with two rows of signal connections and the big heat slug pad in the middle. The signal pads are on a .5mm pitch and this particular line ranges in size from a 9mm square with 108 leads up to a 12mm square with 164 leads. Page 11 shows a CVBGA package that can have 432 balls on a .4mm pitch squeezed into a 13mm square. Lmx9820a_bluetooth_14116bga_150They have dummy components for just about an size package you might run into.

When I was designing boards, most parts were available in SMT and thru-hole, but you could build just about anything with a smattering of different thru-hole DIP sizes. Not any more. ZigBee radios pretty much only come in QFN packages. Some of the newest embedded processors only come in .4mm BGA packages. I could go on.

You just can't hand assembly these bad boys anymore. That may seem to make things more difficult, but not really. If you simply can't do it, you have to send it out and you can get back to designing. At least that's the way I like to look at it, biased, though I may be.

Duane Benson


If you live in the Portland, Oregon area and would enjoy an early Oktoberfest with beer, brats and maybe learn a new thing or two, come to the OktoberBest trade show on September 12th. We will be there in booth 29 and Duane will be speaking about how to avoid layout and assembly got'chas with advanced component packages.

Our friends from Portland State will also be there with us. The Portland State Aerospace Society was recently added to the Screaming Sponsorship Program and they will be there to hang out and chat about active guidance, live telemetry and Mach-3 WiFi. The team is great and is really advancing the field of amateur  rockets.

The exhibit floor is open from 12pm - 5pm and located at the Portland Community College Rock Creek Campus [17705 NW Springville Rd. Portland, OR 97229]. The cost is $10, or a simple donation of food for the Oregon Food Bank.

For more information, you can check out their website at

There is only one...


Other Things...

439pxmtnbiking_sedonamag_2 Do you have other things on your mind besides that design your product manager keeps asking about? Here in Oregon, at least, it's just about perfect weather for almost anything outside. It's great biking, swimming, golfing, hiking, sailing... whatever. I just think you should get outside and do something.

We can help too. Rather than trolling through Digi-Key for a day and a half for parts, you can let us do it. We love Digi-Key and truly enjoy the parts hunt.

Try a Turn-key order from Screaming Circuits. We'll take care of sourcing the parts and raw boards and then build it for you. Use the extra time to enjoy to sun! And don't forget your sunscreen.

Personally, I'd highly recommend it. Of course, I am biased in that regard.

Duane Benson
All your pcb are belong to us

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