Screaming Circuits: September 2009

Top Ten Reasons Electronics is Like The Flu

Frequently when I go to a tradeshow, I come back with a cold virus. I was bound and determined not to with this last trip to ESC, and I almost did or mostly did. I got back home last Wednesday night and I was fine until this Monday. Now I'm all virused up. I sit in a back corner cube so the chances of me infecting everyone else is probably fairly low. And I don't have a fever assuring that it's not the Bovine Flu, so here I am at the office regardless.

Packed in tight

In my semi-repressed-brain state - there's not a lot of activity going on upstairs at the moment - I keep drifting from actual work to strange thoughts, like chips and viruses (as opposed to chips and salsa). Mmmmm Salsa... Software, is of course susceptible to it's own form of virus, but what about hardware? It's not the same thing. But maybe the hardware is more like the virus rather then being the victim of the virus?

#10. The number ten reason that electronics is like the flu: Just when you think you've got it nailed, it all changes. Think the project is done? Oops, there's a bug or some feature creep and you're suddenly sucked back into it again.

#7. Even the same part can come in a large number of different variants and each of those in a large number of different packages.

#6. One vaccine to cure them all? People ask us about stocking standard parts. Like: "don't we have a standard set of passives that we can just pull from because everyone uses the same basic set?" That's a bit like asking why one vaccine doesn't cure all flu types. Let's just look at a .01uf cap. Pretty standard stuff. Right? Well, Digi-Key lists hundreds of varieties of .01 uf cap. What's the voltage? What's the temperature range? What's the tolerance? What's the ESR? What's the package? It's pretty simple - if WE wanted to tell you which cap is best for your design, then, okay, we'd do that. But, we don't know your design. Only you do, so we can't make that decision. We can get the parts here overnight, but we'll only get the exact parts that YOU want us to get.

#5. You need a microscope to see it. Well, we're not quite at the virus size-scale, but it seems to be Flu_und_legende_color_cgetting closer every year. 20 nm etch processes and all. Even the parts are getting close to being not visible by the naked eye. All these 01005 passives and super-micro chip scale BGAs don't look like much more then dust and dust can certainly irritate the respiratory system.

#4. They both make you sweat. Yeah, the old influenza virus will jack up your body temp and make you sweat and ache. So will a tough design on tight deadline. One week to go and you need that proto built up, tested, verified and put into the marketing geek's hands for the press event - that'll cause cold sweats in just about any design engineer just as quick.

#3. Dim the lights. If you've got the flu, you need your rest, so turn off the lights and stay focused on getting well. Staring at your monitor all day, swimming in schematic or PCB layout, all those lights in the background and the glare can make your headache worse. A lot of engineers that I know like to work with the lights down for just that reason.

#2. Drink lot's of fluids. Dehydration is never a good thing. Whether it's dehydration due to the effects of a virus raging through your body or dehydration due to inattention to physiological needs while deep into some VHDL morass. I've heard urban legend of gamers starving to death because they didn't want to drop their guard. I don't know of any stories of design engineers doing the same, but I know how long hours can pass without leaving the chair when stuck on a particularly challenging design problem. Get something to drink! It will keep your mind fresh.

#1. And the number one reason why electronics is like the flu... Full immersion. When you've got the flu, your whole being is immersed in getting through it and giving the virus the boot. When you're deep into a serious electronic design cycle, you're fully immersed into it. The outside world pretty much ceases to exist until you get past the current tough spot.

Duane Benson
I know. I've done the Octal thing before. It's an old joke, but that's what I've got today

BGA Underfill Alternative

Back when RoHS was just an idea, one of the big concerns was the fear of mechanical reliability with lead-free BGAs. A lot of study went into the solder mixes and it's now history, but there is still some concern. Especially in hi-shock prone applications. Sometimes I recommend that the engineer go along with the PCB and just hold the BGA on the board with finger pressure. But that's not terribly comfortable if the board is going into space or down in a tunnel or something like that.

More down to earth, underfill is one of the recommended additions to improve the mechanical strength. We recently helped to qualify a new type of BGA underfill. It's actually a little pad that comes in standard SMT tape and reel and is placed with standard SMT machines. No need to deal with messy goo. It's placed on the board around the BGA pad area and the BGA is placed on top of it. During reflow, it all sticks together and works like underfill. Cool!

If you're interested, contact Randy ( or Dave ( for more information.

Duane Benson

Underfill in tape

Underfill on pcb

Underfill under chip

Musings on Open Source Hardware

I've written a bit about open source hardware before, mostly in reference to the Beagleboard. I'm pretty sold on the concept, myself. But, while open source has become a household concept in the software world, it's still fairly new to hardware. In the case of the Beagleboard, it's really cool because it can give a designer a big head start on using the Ti OMAP processor. Anything from the whole schematic down to just the BGA escape routing can be applied to any design.

But it's not just that. Say I have a little microcontroller board that I've put together. I use it for robots and other sorts of tinkering. It's PIC based and pretty simple. Right now, it just communicates with the outside world via RS232, but I want to add USB to it. I could start with Digi-Key and search for all of the various USB chips and spend hours digging through data sheets to see which one looks best/easiest to implement for my application. Or...

Beagleboard USB

Arduino USB

Or, I could take a look at the schematics for the Beagleboard and the Arduino. Beagleboard is open source hardware based on the ARM Cortex-A8 OMAP3530 processor from Ti. Arduino is open source hardware based on an 8-bit Atmel microcontroller. They both have USB interfaces and I know that both boards work well and have been pretty thoroughly debugged.

Here's two examples that a lot of other folks have already spent time on. I want to spent my design time on the unique parts of my board - the things I've done to make it easy for the types of projects that I want to do with it. USB is USB. I don't want to spend my time doing something that a million other people have already done. I can take a look at the two approaches here and pick one and be done with it. I don't have to dig through web sites to find data sheets and then try to interpret the manufacturers reference design and hope it was fully thought out and tested. I hate that. Some chips come with great reference designs. Some don't come with any and some come with half-baked schematics that only work in the very specific test environment of the chip company's lab.

I know these two work. I can pick one, plop it into my design, make sure I give proper attribution and then just run with it. Very nice and a big time saver.

Duane Benson
Eeny, meeny, miny, moe
Catch a usb-controller by the Vcc.

More Thoughts on Education

This is a follow-up post to one I wrote yesterday about education and new chip technologies. Well, the whole post wasn't about that. But part of it was.

On the flight home, after I wrote the post, I sat next to a rather brilliant Georgia Tech EE and chatted a bit about this issue with him. He's a lot more recent from school than I am and has spent a lot more time on campuses then I have in general.

His observation was very different from what I've heard. He talked about huge grants from private industry and government, research centers set up by private industry at universities and all of the micro-technology research and development that goes on at these places. So maybe the outlook isn't grim at all - at least in many schools.

My guess is that there's a bit of a "have" and "have-not" scenario going on here. If young folk can get to the good schools, the money and the technology is there. If not, then it's a case, like I mentioned, of being Punch-cardprepared for a job that doesn't exist anymore. So, maybe we should be proud of parts of our educational system and yet still looking for places to help with the "have-not" schools.

When I started school to learn how to program, we were still using - yes, it's true - punch cards. We'd write up our COBAL, RPG II and FORTRAN programs in punch cards and feed the deck of cards into an ancient boat-anchor of a card reader to be sent across the state to run at a University computer (An Amdahl 370). In short, we were being prepared for jobs twenty years in the past. It was like time-travel. We did eventually get a little Prime mini computer and a bunch of Apple IIs, but the card reader stayed on as well so I certainly understand this issue.

Duane Benson
Herman Hollerith says "what?"

Over, But Not Out

Well, not out yet. I hope I'll be out when I take to the skies soon. Out sleeping anyway. Not out on the wing. Brrrr. I am out of Empty airportthe show and occupying space in a mostly empty airport terminal. I left the floor just a little early to catch a flight home tonight and I still have about an hour before boarding.

I didn't get to explore much of the show this time. In fact, I barely got out of my booth. I guess that's a good thing. I did get to talk to quite a few folks, including a number of people from colleges and Universities.

Some of these chats were actually a little disturbing. In almost all cases, the students and professors said pretty much the same thing: They limit most of their design education to components that can be hand-soldered. While I do understand the economics, that theme gives me a lot of concern. So many of the new chip designs are being produced only in super-small packages. Who's going to create new advanced designs if our students are being taught in thru-hole and old, large smt? It sounds like they're getting prepared to take design jobs in 1984.

It's not always possible to learn on a thru-hole version and then later in professional life, just move to the tiny parts. Many of the new chips don't have thru-hole versions. And with the small parts, there's a whole slew of things that need to be considered that just might not matter with big parts - paste stencil patterns, via-in-pad, escape routing, cap and inductor proximity, and on and on.

I'm not sure what the solution is. We'll have to ponder on it for a bit, but it seems like a pretty important problem to knock off.

Duane Benson
We don't need no thought control, but we might need some frequency-drift control

ECOsystem at ESC

Traditionally, speakers and vendors spend time at the Embedded Systems Conference educating design engineers on new chips, new techniques and difficult design challenges. Left out all too often, though, is the end-game - bringing it all home - packaging it all up - building it and shipping it. You can't underestimate the value of this conference, but the end game is still missing.

On Tuesday, just across the street from the convention center, at the Hilton, five companies deeply involved in the hardware design industry met to solve just that problem. Digi-Key, NXP, National Instruments, Sunstone Circuits and Screaming Circuits came together to discuss an ECOsystem designed to make the engineers job easier. The companies collectively cover components, CAD, PCBs and assembly and have formed an industry work group to improve the systems and processes needed to take a schematics to a finished product. The first ECOsystem meeting took place at the APEX show late last year and since that time, the partners have developed a statement of work and specific plans for company-to-company collaboration.

Today, CAD systems, components, pcbs and assembly, while in theory, are interrelated, in practice are disparate tasks for an engineer. Components may be well documented and easily available, but new ones can't easily be used in a CAD system because of the lack of up-to-date libraries. It's not too difficult to build a Bill of Materials (BOM), but because of parts availability issues and substitutions, it's out of date almost as soon as its made. PCBs are available, but the process is fraught with chances for error due to limited standards and the outdated Gerber file format. Assembly - especially in prototype quantities - is a mystery for engineers that until recently had purchasers doing the work for them.

Digi-Key, NXP, National Instruments, Sunstone Circuits and Screaming Circuits plan to streamline this phase of the development process with new on and off line tools, collaborative projects and joint offerings. Keep and eye on the ECOsystem partners to see what new developments are in store to make the job of producing electronic designs easier for the engineer.

Grape Power from Ti

Here at the show, we ended up next to Texas Instruments and I spent some time talking with Adrian, their Product Marketing Engineer for the MSP430 ultra low-power MCU. He brought over one of his demo boards which has to be just about the coolest thing I've seen at the show.

MPS430 grape power 002sm

Plenty of things need low power and there are lots of little 8-bit processors that use flea power, but his MSP430 is a 16-bit processor that runs so efficiently that he's powering it with three grapes. He stuck copper and zinc electrodes into grapes - I think they're seedless - and is running it as a clock (as in tells time type clock).

In the picture, here, it's setting next to a Beagleboard powered by it's uncle, the OMAP3530. We built this particular Beagleboard, but we didn't build the grape clock. Pretty clever stuff.

Duane Benson
I wonder if the grapes still taste okay after all the electrons switch sides like that...

H1N1 in Microcode

Booth 909 003

It's opening day here at the Embedded Systems Conference, Boston, 2009. For those of you that stop by our booth, we have a number of things to offer:

You can learn about our pcb assembly services, you can enter to win up to $2000.00 in assembly labor with us and you can spread the swine flu if you've got it. Well, hopefully not that last one. We're keeping our handy-dandy bottle of hand sanitizer close by. It's 62% ethyl alcohol and maybe 38% generic goo and bubbles. I'm hoping that will do the trick. We smeared it all over our ethernet cables to keep the viruses out of our computers and beagleboards. My laptop is using wireless, so I should probably sploit a bunch on it too.

We'll be giving away the assembly labor to one person that registers each day. (two total prizes and we'll notify the winners after the show).

Duane Benson
Stop by and say hi. Or walk by and start to cry.


At the ESC Show

From the ESC show floor...

Booth 909 (Small)

Actually, set up is done already. It went pretty quick this year which makes me question my sanity in choosing to leave Portland late Sunday night on the overnight flight. Still, I'm paranoid that if I did get here at 4:00, I'd hit a traffic a jam, the booth parts would be lost in the warehouse void and my hotel room would have been given to someone else.

Duane Benson
Now I need sleep...

Layout 101 in 1989

I just noticed a twitter tweet about my most recent via-in-pad post: "I could understand this if it was 1989, but egads, thats layout 101 @pcbassembly A Few More Via In Pad No-no's", from mnphysicist.

I tend to agree that this is pretty basic layout advice in that post of mine. The ironic thing though, is that back in 1989, this type of problem was probably much less common than it is now. The company I worked for at the time had a number of electrical engineers and a CAD layout engineer. The electrical engineers did all of the schematic work and handed the completed schematic off to the layout specialist. The layout engineer knew all of these type of things as well as all of the FCC, UL and other regulatory issues. I think that was pretty typical back then.

Our boards rarely had problems like this. These days, though, a lot of those layout specialists, along with documentation specialists and other technical resources have unfortunately been laid off. That leaves the design engineer to do the layout as well as the schematic. We find that quite a number of these folks entered their career without a lot of training in layout. It's a different skill set than circuit design and some folks have both skills and some don't.

It also doesn't help that so many of these components are getting so much smaller and many of these designs are going into space-critical applications. This pcb had a lot of spare area to work with, but a lot of them don't.

Duane Benson
Take it to the other side

« August 2009 | Main | October 2009 »