Blog - Screaming Circuits

New Super Small BLE Chip

ATBTLC1000 on coins from Atmel siteI tend to get quite excitable when new, smaller, components come along. The smaller, the better.

While, I haven't yet seen it up close and personal, I've seen the announcement and datasheet for a new SoC (System on Chip), with Buetooth SMART BLE 4.1. The whole chip is 2.2 mm X 2.1 mm in a WLCSP (wafer level chip scale) packaged BGA. (Image from the Atmel web site). The part is the Atmel BTLC1000, with BLE and an ARM Cortex M0, running at 26 MHz.

ATBTLC1000 dimensionsIt's got 32 balls, in a staggered pattern. That gives the chip a diagonal ball pitch of 0.3535 mm. That's really small. The staggered pattern isn't too common, but I expect that we'll be seeing more of it as parts continue to push the size envelope down.

Here at Screaming Circuits, We've built a few 0.3 mm pitch devices, and plenty of 0.4 mm pitch parts. I wouldn't anticipate any problems, but if you do get your mitts on one of the things, you should probably take the mitts off (because you'll loose the part) and call us and ask to talk it through with our manufacturing engineers before sending it in.

Duane Benson
There was a demon in the oven. They said whoever solders him would fry. Their pads would bridge, their pc boards would twist and warp. The demon lived at 0.3 mm pitch on the metric scale, 0.0118121 inches SAE. But not at Screaming Circuits. That demon's afraid of us.

Fuzzy Logic in Manufacturing

In the digital world, we're accustomed to everything being driven by the absolute 1 or 0. You can also add in Tri-stated too, but that doesn't really count for computational or conditional logic. Analog allows for degrees of data, but at some point, is still driven by a specific cut off point. To start to understand the concepts of "more correct than incorrect", we need fuzzy logic, which is used in digital computers, but requires a lot more computation than a simple on / off switch.

Our parking lot takes a short-cut to fuzzy logic with cats. We've got a field across the street that has a small population of feral cats. They seem to be happy and healthy enough - although some mystery person does bring some food. I suspect that they'd find enough to eat regardless, but the extra food stacks the deck a bit in their favor.

Corporate cat on car 1024As the temperatures drop in the fall, it's not uncommon for them to hop up onto the warm hood of a recently arrived car, as this one did this morning.

I've heard that in the wild, cats can be quite vicious predators. In fact for the most part, I think that, while if dogs were larger than us, they'd be happy to let us use them as beds, cats larger than us would eat us. But, as long as they aren't eating any of the PC boards or parts that come through here, I don't mind having them around.

Duane Benson
Fuzzy Wuzzy was a bear
But he had no microcontrollers to play with

Continuous Strips of Parts

Not long ago (No Need To Waste Parts), I wrote about the use of tiny cut strips here at Screaming Circuits. That's good information, but only part of the story. (When has anything ever been the whole story???).

IC cut stripThere may be some times when you don't want to buy a reel, full or partial, but still want your parts all in one continuous strip. Everyone wants to use up their odds and ends, but once those are gone, it's easier for you if each part is just in one strip. If you want to save a little money here and can use a longer turn-time, you might want to pick our Short-Run production service. If that's the case, you will need to send in continuous strips. Short-Run requires reels or continuous strip of at least 12" in length.

There are two questions you'll probably ask:

1.    How can I make sure my parts add up to at least 12 inches (305 mm)?

There are two ways to do this. First, if you have some of the parts, measure the length and calculate the number of components per inch. Use that to determine the number of parts you need to get 12 inches.. Make sure to calculate the length based on the quantity you need + 10% (+50%) with 0201 passives).

If you don't have any of the parts already on hand, you can download the datasheet for the component. In the pack, you'll usually be able to 

If the length comes out to less than 12 inches, use the parts per inch to figure out the total you need. If it comes out to 12 inches or more, you're set. Passives commonly come in 2 mm pitch tape or 4 mm pitch tape.

2.    How can I make sure that my supplier sends my parts in continuous strips?

It's not uncommon for DigiKey or Mouser to send 50 parts in 5 different strips of tape. I've even received parts in strips of one. Each part was still in the tape, cut from the reel. They were just cut into strips of one. We can use those in our Full-Proto service, but it's a hassle for you and you can't use them with Short-Run.

Neither distributor has a setting for "continuous strip", however, they do have a place to enter special instructions. Simply state in the special instructions that you need uncut, continuous tape for all parts that come in strips of tape.

Duane Benson
What is the airspeed velocity of an unladen swallow?

Those Danged LEDs again.

I fell into one of my own favorite traps last week: the dreaded LED footprint mess.

I designed a board based on the Microchip PIC32 - it's a ChipKIT Arduino-compatible board - that has a number of RGB LEDs. on it. I used Part number LTST-C19HE1WT, from Lite-On. Their datasheet is easy to find, and they put the footprint information right up front, just the way we like it.

Almost all is well, but I somehow missed taking my own advice, and I didn't double check the footprint.The footprint I used is more or less 180 degrees off from this one. The common Anode is still on pin 4, but the numbering is different. It's got pin one in the same place, then pin two is in the lower left. Pin 3 is on the same place, and pin 4 is on the upper right. That's the conventional pin numbering order.

Fortunately, the fix won't require any mod wires. If I rotate the LEDs 180 degrees, the anode will be in the right spot. All I'll need to do is adjust my software for the correct R, G, and B pin locations.

Duane Benson
I'm dizzy with rotation

PCB West - September 16, 2015

Come join us!

If you're going to be in Santa Clara, California, on September 16th, drop in to the Convention Center. Screaming Circuits will be there, along with our PCB fabrication partner, Sunstone Circuits. We'll be in booth 510, and they'll be in 508.

While you're there, ask us or Sunstone about a special offer you can get by using both of our services.

But wait! There's more! I'll be speaking on best practices at 4:00, on the 16th. Look for session 38: PCB Design: Best Practices for More Reliable Manufacturing. in the conference program guide.

Here's a handy show floor map:

PCBWest 2015 floor map

Duane Benson
Do you know the way to San Jose?
Then, turn left and go Northeast
'cause we'll be in Santa Clara

Disruption and The Internet of Things

Every few years something new rears its head and changes everything. The old rules break, convention gets unconventional, storied institutions get shaken to the core. We call this, "Disruption."

Automobiles disrupted the horse and buggy industry. Airplanes disrupted the passenger ship industry. Computers disrupted the typewriter industry. In 2003, Screaming Circuits brought disruption to the electronics manufacturing industry by bringing it online, with performance and flexibility previously unheard of.

The latest disruptive current is the Internet of Things (IOT). It means everything will be connected. Everything will be intelligent, and everything will be complex inside.

I recently spoke on "The Peggy Smedely Show", a part of the Connected World Network, about disruption, the IOT, and how Screaming Circuits is, again, driving disruption, this time by helping enable the IOT. 

Give yourself a little over twelve minutes and hear what I had to say.

Duane Benson
A QFN says "What?"


Running Out of Time - You'd Rather be up on the Mountain

How many times can the project manager come in and ask how the PC board design is doing? Why can’t management understand that it’s difficult to say how long it will take to do something that’s never been done before? This is totally new ground. It’s innovation in its purest form. And you, the designer are driving it home.

If only you could squeeze a few more days into the week. If only you could have the confidence that the boards will be built right – this is complex stuff, with wafer scale 0.4mm pitch micro BGAs, QFNs all over the place, and 0201 resistors and capacitors sprinkled around like salt and pepper.

 - You can squeeze more time in. You can be assured that the complex parts will go on right. You can keep the boss happy. Screaming Circuits quick-turn assembly service can build your job remarkably fast. Mount_Hood_reflected_in_Mirror_Lake,_OregonShort deadlines and difficult boards are our bread and butter.

It’s 6:00 pm on Friday. Hit “save” on your CAD file for the last time, and hop on over to A quick quote, order, and files upload, and you’re off to join your college buddy on the climb up My Hood you’ve been talking about for a month.

Don't delay, the mountain awaits your boot prints.

Duane Benson
Because it's there...

What's In Your Way?

If you're attempting to cross the median of a busy four-lane highway, it's entirely possible that there's a Jersey Barrier in your way. In that particular setting, having something sturdy blocking your way is probably a good thing. On the other hand, I would bet that, for the majority of you reading this, there are some barriers around you that you'd much prefer not to run into.

Jersey barrier dimensionsBarriers can bring on stress, uncertainty, risk, and a general sense of despair. Despair can lead to hopelessness. Hopelessness can lead to you being rolled up in a fetal position under your desk, tangled up in the nest of cables that every good engineer has under their desk. As everyone knows, if you're under your desk tangled in cords and whimpering when your boss walks in the room, you're probably not going to get a Christmas bonus.

That's where smart outsourcing can help. We talk about PCB Assembly as being our thing, but conceptually, it's more of a case of us trying to remove some of your barriers. We'd prefer that you get your Christmas bonus rather than getting carted off on a gurney, too afraid to open your eyes for fear of the glare of your abandoned co-workers.

Here's what we suggest:

  • Spend a little extra time on design review to increase your confidence (ever find an overlapping trace the day after sending the design out?) 
  • Double check that your BOM and or parts kit is current (If you chose the parts a few weeks ago, some may have gone out of stock)
  • Drink some water (dehydration can interfere with a clear, logical thought process)

If the extra day or two doing so causes a problem, just order a faster turn-time.

Duane Benson
129 °F in June of 2013?!
Well, what did you expect from a place called "Furnace Creek"?

No need to waste parts

We love parts on reels. Who doesn't? But reels aren't always practical - and it's not just about cost. Cost is, of course, important, but there may be other factors to consider.

Say, for example, you need 20 2.2K Ohm, 5% 0805 resistors. You could buy a small strip of 25 from Digikey for $0.32. That gives the 20 you need, plus a few spares just in case.

Alternately, you could buy a digi-reel ( a custom quantity reel). On the reel, you'll probably want more parts to keep the strip long enough for the feeder. Let's go with 250 parts for $1.39. Digikey charges $7.00 extra to create a custom reel, so that's a total of $8.39. Still peanuts.

For a third choice, you could just buy a full reel of 5,000 for $10.64. Still peanuts. If you're gong to need the same part for a lot of designs, this might make sense. But, there's more than just cost to consider. You need to store and ship it. Shipping two dozen reels gets pretty expense. Storing and inventorying several dozen reels can become a hassle too.

Cut strips on plateThe beauty of Digikey, Mouser, and other places that sell cut strips is that they essentially become your parts warehouse. You pay the $0.32 cents and never have to worry about whether the part is in your inventory, how many are in your inventory, digging it out of wherever you stuffed the reel when you last needed it...

If you do buy and store the whole reel, you don't need to ship the entire reel to us. Just cut a strip with the number you need, plus about 10% for that "just in case" (50% extra for tiny 0201 parts).

Of course, if you need a few thousand of the parts, go ahead and send us the reel. It would make sense then.

Duane Benson
Reel, reel your part
Solder it, solder it, solder it, solder it
Cost is but a factor

Packing Parts for Personal Manufacturing

Manufacturing, especially small volume one-time-only builds (like a prototype) is hard. It's not wise for most people to actively seek out chaos, but that's what we do, and we do it wisely. That's what we've been doing since 2003. 

We do it because it's hard and because it's necessary.

A big part of quality manufacturing involves risk reduction. Prototyping and quick-turns inherently add in a lot of risk. While we've designed our processes and systems around turning that risk into a quality product, there are a few things that you, the customer, can do to help reduce risk even further.

One of the best things you can do to reduce risk is to prepare a well organized kit, as shown in this video.


You can send us your parts in short, cut strips, like you get from Digikey or Mouser, long continuous strips, full or partial reels, tubes or trays. We machine place from all of those types of packages. What's important is clear labeling and organization.

Individual, or mixed/loose components are not good, though. Pins get bent, leads get contaminated, values get mixed... Leave them in the strip, even if it's short. If you've got multiple short strips of the same part, we can still machine place. Don't tape them together. We can deal with them as is.

Duane Benson
Peter Piper Picked a Peck of Pickeled Manufacturing