CAD This or CAD That

I use Eagle CAD a lot. I can get away with the "Light" version, because the designs I create are small and non-commercial. I do use them sometimes to illustrate points here on my blog, but I think that still meets the qualifications of their free version. It's a good program and the multiple license levels from the free version up to the full professional version add a lot of flexibility to have the software grow with you.

Our partner, Sunstone, builds most of our PCBs here, which is a nice segue into an alternative CAD package. There are a lot of reasons to pick one CAD package over another. I won't go into that here because those reasons tend to be specific to the application. Most CAD packages are sold as a lump-sum purchase up front. A lot of them also have yearly license renewal fees. That works sometimes, but there are other times where up front costs are more important. The model that Sunstone uses for PCB123 is to provide the software at no charge and just add a little tiny bit of the software cost onto the PCB board purchase.

PCB123 isn't the only package that follows this business model and is tied into a specific PCB vendor. But, as far as I can tell, PCB123 is the only package of its sort that has enough capability to be a viable replacement for more traditional pay-first CAD packages.

I recently downloaded V4.1.11 and have started to run it through my own personal "can I use this for my stuff" test. I know it's a good package because we, here at Screaming Circuits get boards of all sorts designed with PCB123 to assemble from all manner of company. But, something can be a good package and still not fit an individuals specific requirements. Hence my personal tests.

I do find it odd, but not really an issue, that it starts you off in the layout editor instead of the schematic editor for a new design. Oh well. One click and I'm in the schematic where I can search for my parts. I use PIC chips and it's pretty rare that I find the exact chip. I always seem to have to find something close and then modify it, which just adds more opportunities for error. I know there's a jillion 28-SOIC,M28B_sml varieties, but once in a while it would be nice to just find the actual part.

Fortunately, today I'm looking for PIC18F2320 in an SOIC package. Fortunately, because it's actually there! I hit the "Insert" menu and choose "Add Part". Then I put "PIC18F23" in the search box, and there it is, but not on the computer. It was in their online labraries. (In the cloud?) It took all of about 15 seconds to automatically download the library footprint though, so first test = passed.

And the really cool thing is that once I have that part in there (for the parts found pre-made in the library), I just select the "Bill of Materials" tab down on the bottom and I can see if DigiKey has the part in stock and how much it costs.

Duane Benson
If it's in Oregon, the "cloud" is probably a rain cloud

Short Cuts Don't Always Make Long Delays

The saga continues. I have my parts kit. The PCBs should be here from Sunstone tomorrow. When I placed the order on our website, I estimated that I'd have the parts and PCBs today, but I wasn't really sure. I knew there would be a chance that it would be tomorrow, but I thought it would be good to see how our communications goes when something is late. Obviously, an assembler can't start building until the parts have arrived, so the Industry standard is to start the turn-time once everything is in the shop.

If a box is late and the sender doesn't know it, unintended delays can be added into the process. Knowing this, we recently did a lot of work to improve our communications, on such issues as late parts, to help reduce delays. Sure enough, I dropped on over to the website and right on the top of the home page is a note that I have an issue (late parts) with my job. Tonight at midnight, I should receive an email telling me the same thing too.

On the subject of the PCBs, I sent Gerbers to Sunstone. That works just fine, but I'm always a bit nervous about the accuracy of my layer mapping. They double check, so I've never had problems, but I still get nervous.

If I'd waited a few days, like until today, I could have taken a short cut by just sending in my CAD board file - they just started accepting native CAD files. You can still use Gerbers, but if you use Altium, Eagle, OrCAD, National Instruments Circuit Design Suite, Ivex Winboard or PCB123, you can just send in the board file and save some time and hassle.

When I get the boards tomorrow, I'll pack everything up and deliver it to the receiving folks. Then I'll see how the rest of the build process goes from the other side of the fence, and I'll see how we deal with extra parts. I did that on purpose also. With a couple of parts, I'm delivering several hundred more than I need. With a few other, just the requisite 5% over. It will be interesting to see just how I get the extras back.

Yes. I know. I work here, so I shouldn't have any doubt about how all of this stuff works. I do know how it goes, but it's always a good thing to, every now and then, check and see how well practice matches up with theory.

Duane Benson
Grip, Fang, Wolf! Guard the mushrooms!

Faster, chug a chug. Faster, chug a chug...

Ever long for the days when you could lazily send out your files to get boards fabbed and a prototype assembled and then have a leisurely couple of weeks waiting for it all to completed and returned? Well, we're not going to help you get back to that. In fact, we try to do the opposite. Let's make everything speedier and speedier. I hope that's okay.

Screaming Circuits' PCB fab partner, Sunstone Circuits just added in a bit more to that end. Back in the olden days, if you needed PCBs fabbed up in 24 hours, you had to stick with two-layer boards. Not any more. They recently started offering four-layer PCBs fabbed in 24 hours in their PCBexpress quick-turn service. No rest for the weary. That's especially cool if you're having signal integrity problems and need to add in a ground and/or power plane layer.

Duane Benson
If by approaching the speed of light, time speeds up for you,
does time slow down for you as you approach "stopped"?

A Little Something Extra

Most of what we do here at Screaming Circuits is PCB assembly. We build prototypes and short run production - putting parts on boards. We actually do more then that though. Our parent company, Milwaukee Electronics, has been around for about 60 years building volume production and providing custom engineering design services.

WhenMR early layout 150 we started Screaming Circuits, in 2003, we decided to just focus on the prototype assembly - putting parts on boards. That's been a pretty good deal and we're happy with it. What's been happening lately though is that we've been getting more and more requests for higher assembly volumes and for engineering design services. We put together our ShortRun production offering last year to answer the first request. For the second, we've been gradually connecting our engineers with folks that request such services.

Check out our Design Engineering Group.

Duane Benson
"I like nonsense; it wakes up the brain cells" (Dr Seuss)

A New Place To Find Screaming Circuits PCB Assembly

Screaming Circuits and Sunstone Circuits have partnered for board fab and assembly for many years and now, we've made things easier for our common customers. You can order Screaming Circuits Assembly at Sunstone while your order your board fab.

Just order your boards from Sunstone like you always have, but on the quote page (for PCBexpress or Full Featured PCBs), check the box labeled: "NEW! Quote & Order Assembly" as shown in the screen capture below.

NEW quote

Check the box pointed at by the big red arrow I added in to the screen capture above. Then, you'll get a Assembly options_cbox to pop up with two choices: "Drop Ship Assembly" and "Bundle Assembly". If you select to drop ship with the button "Select Assembly", after your boards are fabbed, they will be sent directly to Screaming Circuits. With this option, you'll have to go ahead and come to our website and place your order separately before the boards get here. We've had that option for quite a while.

If you choose the new option, to bundle, by clicking "Quote Assembly" you will see a quote form and you'll be able to quote and order your assembly rightAssembly quote_c then and there. The order will be placed with us, the boards will be shipped to us and you'll get fully assembled boards from us. You will still have to send us the parts and make sure we have all the files we need though. We'll get your order ready in our system and give you a call to make sure that we have everything that you need.

You can, of course, still order your boards and your assembly separately. That's not a problem at all, but if you are getting your PCBs fabbed by Sunstone Circuits, we hope this added feature will make your job just a little bit easier.

Three Years And Posting!

Hey - I just realized that today is the three-year anniversary of the Screaming Circuits blog. Cool.

This is post number 311, so that's just over 100 yer year. Three years really isn't that long in the grand scheme of things, but I suppose in Internet years, it's pretty okay.

My first post, was, as is the case with many blogs, mostly useless. On the other hand is

int main()
printf("hello, world");
return 0;

mostly useless? Those few lines of code have started countless developers on to writing trillions or maybe hundreds of lines of code. Okay, so I'll call it lame, but not useless. How's that? But, speaking of useless, here's some useless blog trivia. According to Wikipedia (which we all know is 110b% accurate), Justin Hall, back in 1994, was one of the first bloggers as was Jerry Pournelle. Hmmm. I'm not really sure how to come up with the exact first blogger. It may not even be possible to identify the first one.

Back in the day, I used Compuserve to host my website which had some characteristics of a blog. (I discussed the value of a website for businesses) but it wasn't really the same thing. I remember reading Jerry Pournelle in Byte Magazine way, way back. But that was in print so we can't call it a "blog" in the sense of "web-log". On the other, hand, why is the specific technology all that important? He was journaling to a broad audience. He just couldn't do so on his own time-scale and comments had to come back through postal mail. Certainly, I enjoyed his musings and his plog (print log???) was one of the reasons I read the publication. That's got to count. Anyway, I have no idea when the first blog was written.

Back in 2006 when I started this thing, I didn't really know what I would do with it, but I hope it has been of value to some of you folks. It just seemed like a good way to pass on hints and tips and help other folks make better pcbs. And here, 311 posts, about 90,000 words, half a million key presses later, it's September 14, 2009.

Enough of this. I have a tradeshow to prepare for.

Duane Benson

August Special

SunStone_logo_saturated 120  Let us make your job easier. You need PCBs anyway, so have us get them for you from our partner For any orders placed during the month of August, 2009, all you have to do is ask and we will get the boards from Sunstone for you and we'll just pass the normal Sunstone price along - there won't be any markup or service charge for providing this service.

This offer only applies to boards from Sunstone. PCBs from other board houses and parts will still have our normal turn-key service charges applied. Your order must be place via the website prior to midnight on August 31, 2009 or via phone prior to 5:00pm PST on August 31 and the boards must be purchased for an assembly order with us.

Q&A for this special:

Q: What if I normally use another board house?
A: Give Sunstone a try. They do great work and have great service.

Q: What if I just want to submit a kitted order but still want this special?
A: Just tell us that you want us to get your boards from Sunstone too. Put it in the special instructions on the web order or tell us if you're placing a phone order.

Q: What if I still want to use a different PCB supplier?
A: That's still okay with us. You just won't get the special.

Q: What if I already bought my boards from Sunstone?
A: I'm sorry that we can't give you any discounts on that order. You'll still get great service from both companies. Just stay tuned for our next special or maybe you'll need more during August.

Q: What if I'm looking for some kind of board for my house and not for electronics?
A: Home Depot carries a wide variety of boards of the non-printed-circuit variety. You might try there.

Q: I just placed an order today and I know you guys haven't started work on it. Can I get this special on that order?
A: As long as we haven't started work on it and you can accept that we'll probably have to add in some time to get the boards, then yes. Just give us a call and make sure we haven't started, tell us you want the special and accept the extra time. Cool!

Duane Benson

RoHS temps may still kill RoHS parts

I've written about a few cases where alleged RoHS compliant components don't always hold up in the face of RoHS reality. Our friends over at ECD have been studying the problem and coming up with solutions to best eliminate the problem. They make thermal profilers for reflow ovens. We use their products here at Screaming Circuits and that's one of the reasons we have such good reliability with our assembly work.

If you're going to the APEX show in Vegas an the end of the month, you can drop in and see them in booth #1628. Until then, here's a bit they have to say on the issue:

EMS Alert: Would you rather be part of the problem, or part of the solution? Elevated Pb-free temperatures can cause hidden damage!

The new IPC standard released Dec 08, Classification of Non-IC Electronic Components for Assembly Processes, J-STD-075, calls for thermal classification of components, and recommends a marking system to help contract manufactures recognize component temperature limits during the soldering process. The release of the standard follows a comprehensive study by IBM on this issue, and substantiates what we at ECD have recognized from field reports.

The IBM study shows that these higher temperatures are dramatically shortening life expectancy of components, especially more sensitive passive components. Failures don’t show up during initial test, but much later on in the product’s life – often six months to two years later, and well below forecasts that drive pricing and warranty policies. ALL parts have temperature limits; and until we take the time to profile the process to which we subject these parts, we can’t know if we cause harm or not. The IBM study has done much to provide such characterization, so there is little excuse to proceed in the dark.

We have, over the past year, written several articles (see links below) pointing out that with increased solder process temperatures, specifically for lead free solder, it is more critical than ever to make thermal profiling a process that takes into consideration the most sensitive of components. A comprehensive program is needed, and ECD has moved in that direction with our Thermal Quality Management (ThQM™) Program. We think this will give the industry the knowledge and tools to look at ALL components in the comprehensive light necessary. Equally important, it introduces a program and method of dialog between OEM and EMS provider on soldering process issues. Finally, in keeping in the “standards” vein, the Thermal Quality Management Program suggests a process, with corresponding checklist, to assure both OEM and EMS provider that no damage was done during the soldering process.

An ECD representative will make an APEX presentation on Thermal Quality Management on Wednesday, April 1, at 12:30 at the combined Circuits Assembly/Global SMT & Packaging Booth # 1383/1385, and will be available for questions at our own ECD Booth #1628. You can also visit for more details on ThQM™ and to sign up for free online classes on this subject.

ECD Articles:
Thermal profiling optimizes printed circuit board assembly
Thermal profiling: A key element of process control
The IBM study

PCB123 ZigBee Robots, Part Four

This is the third or fourth in this series. I paused for a while and just picked it back up again. As I eat my soup and write this, it occurs to me that I've given each post a different name so if anyone actually wants to follow my progress, I've made it quite difficult to do so. I'll recap first and then later, try to be more consistent with post titles.

  1. It all started at the ESC show back in Boston with this post called "Easy Zigbee" about some ZigBee modules I found in the Microchip booth. You'll note that I'm using Microchip components in this series, but my sister company, MEC Innovation, uses a lot of Atmel chips. We like both company's chips here. Especially with good salsa.
  2. Next, I wrote about my plan in "ZigBee, Part two".
  3. The most recent post in this series was "PCB123 QFN Footprint". That's where I started with the CAD package and I got stalled with the parts library.

From now on, I'll identify this series as "PCB123 ZigBee Robots, Part X".

Anyway, enough of that rubbish. I've picked it up again and this morning created the library part for the QFN28 PIC18F2321 microcontroller. I'm lousy at building footprints so I consider that a major accomplishment.

I have a couple more footprints to make - a DFN8 regulator and a CSP BGA RS232 chip. I muddled through the microcontroller but after I do those other two chips, I should be clear enough to able to post some hints on how to make your library components in PCB123.

Duane Benson
Later - I'm going to finish my soup now.

Financial Fear and Uncertanty

I'm really old. I remember Black Monday back in 1987 when we all thought the business world was coming to an end. I was working for a company called Metheus at the time, making high resolution graphics systems. I remember when Microsoft lost half it's stock value in 2000 precipitating the dot-com crash. I was just a kid during the energy crisis back in the early seventies, but we all thought that was the end of the American economy. I remember that double-digit inflation back in the 70's and the double digit interest rates in the 80's.

It comes and it goes, you know. I've kind of lost track of the number of business "doom cycles" I've been through and the number of times "experts" have predicted the end of U.S. prosperity. Personally, I'm seeing this as a time to start putting more money into my 401K.

I do know though that when credit gets tough to get, a lot of companies tighten their belts. A lot of small companies retrench and bigger companies cut back. Unfortunately, for us mere working mortals, our work load never seems to lighten up. In fact, it frequently gets worse.

We here at Screaming Circuits are lucky in that we've been growing and expanding. This month we're adding a new surface mount line. We are very strong and we'll be here through this financial tumble to help if you need it. We hear rumors of pcb fab houses struggling and other ems shops struggling. I hate to hear that about any company or any industry, but I would like to reassure you that we're set to keep running at full speed. We're continuing to expand our capacity and improve our quality and service. We are here for you.

Duane Benson
When the going gets tough, the tough eat ice cream