This technical information has been contributed by
Sigenics, Inc.

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Is a Custom Circuit Right for You?

Custom Circuit

Mark Shortt
Editorial Director
Design-2-Part Magazine

A specialist in the design and fabrication of application-specific integrated circuits works at the leading edge of electronic product development.

Innovation—in product design, development, and manufacturing—can play a huge role in building a healthy U.S. economy, and recognition of its importance is on the rise. But as appreciation for innovation grows, so does the need to protect the intellectual property (IP) that made it possible. Sigenics, Inc., an ISO 9001:2008 certified company that provides integrated circuit (IC) design and fabrication services to start-up technology companies, research laboratories, and OEMs, offers an effective means for product makers to protect IP secrets: custom-designed and tested silicon ASICs (application-specific integrated circuits), or custom micro circuits.

The Chicago-based company says that custom integrated circuits can help makers of electronic equipment protect intellectual property and reduce costs associated with the size, power, and assembly of the end product. An ASIC's compact circuitry can also reduce problems associated with electromagnetic interference (EMI), according to the company, while also providing better noise, bandwidth, and leakage performance.

Sigenics' specialties include analog circuit design, wireless power links, and small-volume manufacturing of microelectronics for numerous markets, including biomedical, RFID, test equipment, aerospace, military, and industrial controls. The company's team of IC designers works closely with a customer's engineering team throughout the specification, design, layout, and test phases of a project to ensure that the finished device will meet customer requirements. Sigenics will then deliver the custom device to its client in small-to-medium production volumes. The ICs that are designed, tested, and supplied by Sigenics are used in sensor, analog, and mixed signal applications.

The company's three principals, all co-founders of Sigenics, include Philip Troyk, an Associate Professor of Biomedical Engineering at the Illinois Institute of Technology, where he leads the Laboratory of Neural Prosthetic Research; Douglas Kerns, who formerly held engineering positions at Fermi National Accelerator Laboratory; and Glenn DeMichele, formerly an engineer for Harris Semiconductor, Rockwell/Collins Avionics, Northrop Corp., and Precision Scientific. According to the company's website, Dr. Troyk holds 12 patents and is considered an expert in the field of neural interfaces. Dr. Kerns is the author of numerous papers on circuit design, silicon sensors, and synthetic neural networks, and Mr. DeMichele, a holder of nine patents, has authored or co-authored numerous papers on neural interface devices.

Sigenics was founded in 2000 to develop silicon devices to aid in biomedical research. Today, the company employs 12 full time staff in a 2600 square foot facility located in the University Technology Park on the campus of the Illinois Institute of Technology, near U.S. Cellular Field. The company recently acquired an automated wafer prober and added another 400 square feet of space to accommodate the prober.

"We've been on a fairly steady growth path," said Sigenics Engineering Director Doug Kerns, in a phone interview earlier this year. "It was the three of us for several years, and then we got some space and a couple of employees, and now we've got 12 people. We're on a growth curve and we plan to maintain that."

Sigenics recently announced that it has released, to a foundry, a research fabrication run involving two types of wireless diagnostic chips that will be used to monitor and pinpoint the source of epileptic seizures, as well as help neurologists assess the potentially damaging effects of corrective brain surgery. The fabrication run also includes a second generation, implantable myoelectric sensor (IMES) device that sends electromyography signals from an amputee's residual limb to control the movements of a hand prosthesis.

The company has produced bare-die silicon chips for hybrid modules used in avionics, and recently delivered a prototype silicon chip for a wirelessly-powered, industrial-grade sensor. The application requires high reliability over a long service life at high temperatures, and the device must be intrinsically safe for use in explosive atmospheres. According to Kerns, Sigenics drew upon its experience in wireless powered devices and high-reliability electronics to build a successful prototype.

"We really love what we do and we want to have a financially stable platform to do it from," said Kerns. "We love making stuff that works, and that's really what drives us."

Recently, Doug Kerns talked with Design2Part Magazine about Sigenics' services, some of the benefits of custom micro circuits, and what he and his colleagues like most about their work.

 

D2P: How did Sigenics get started?

Doug Kerns: There are three principal owners, and all three of us were, at some time, independent contractors. And after working together on two different contract jobs, one of the three of us proposed to the other two, 'Hey, we work together well; let's make a company.' And so that's how we started. We basically turned into three co-dependent contractors instead of three independent contractors.

D2P: Who are your typical customers or prospective customers—what types of companies or enterprises?

DK: They span a fairly wide variety. Generally, they're people who are trying to design a new product of some type that has an electronic component in it. We've dealt with people building medical devices, avionics assemblies, industrial sensors and controls, lab instrumentation, that sort of thing. But basically, it's anywhere there's an electronic device where there's a very strong constraint on either size or power, or something that drives them to a microelectronic assembly.

D2P: What exactly does Sigenics do for them?

DK: Our value proposition is that we can make a custom electronic gadget for you. You tell us what you need, and we'll design a gadget and build it and deliver it to you. One of the things that we offer along with that—it's a little more subtle—is that we can come alongside our customers and help them understand how to specify what they need. Typically, it's a very difficult task for people who are not already in the electronics business—and, often, even for those who are—to be able to clearly state what the requirements are for a new device, a new design, and then how to specify that as an engineering design spec. So that's a big part of the value that we bring to the table, and then we back it up with design expertise and manufacturing capability.

D2P: Do you have manufacturing capability in house, or do you subcontract it?

DK: We have a mixture. We can do certain types of manufacturing directly in house. We do micro testing; we have wafer probe machines to test micro circuits directly. We can do that in house. We also simultaneously have an ongoing relationship with an outsource [supplier] for wafer probing, and we outsource things like wafer fabrication, which involves nasty chemicals, ultra clean rooms, and things like that. We work with several different companies for outsourcing that. Various steps of assembly we can do ourselves, and we also outsource. So basically, we're a general contractor with our own tool box.

D2P: What are some of the benefits of application-specific integrated circuits?

DK: The general concept of micro circuits is that you take whatever electronic functions you need in your gadget and you compress those down to a single silicon chip—or maybe a couple of silicon chips, if you need something really exotic. Once it's compressed down to a silicon chip form, you have all the different functions on that chip.

It's possible to reverse engineer a microchip, but it's far more expensive and difficult. It's a much higher barrier to straightforward reverse engineering. So if someone's got a product where they feel very sensitive about the intellectual property, having a custom micro circuit as a significant part of their electronics is a very simple way to hide that from prying eyes. It can be expensive: If your volumes are high enough, then building a custom microchip might add cost instead of cutting it down. But some people really want that.

Another thing about microchips is that they're micro—they're smaller than the corresponding other set of off-the-shelf parts. We pay an upfront premium in the engineering of the device, but once you've got it, it's the single object that comprises an entire collection of electronic functions. It might have been a whole giant circuit board before, so it's one way to compress a lot of function into a small space. By the same token, because the pieces are all physically close together, it often takes less electrical power to communicate information from one piece to another, so you can actually get major power savings by going to a custom integrated circuit.

D2P: You describe the Sigenics S5800 Class E Controller Chip as a "power management chip designed to generate a high-intensity magnetic field" that's used to transfer power and data to an implanted medical device. Can you talk a little bit about that?

DK: We build it for ourselves because one of the technical corners that we have expertise in is wireless power delivery. It's used for things like implanted medical devices, where you don't want to have a battery that's got to be changed periodically, because that involves surgery, and you don't want that. We've also used the same technology for things like sensors that are embedded in walls, structural components, or things of that nature.

The basic concept is you deliver electrical power through a magnetic field, so you don't actually need a wire connection. But to do that, and also to deliver data along with that electrical power, you have to have a thing that can generate the magnetic field, modulate the frequency of the field, and control all of that. It's a fairly complicated bit of circuitry. It's doable, it's pretty straightforward, but it's complicated enough that when you do it several times, you realize that it would be handy to have a ready-made part that would do all that fancy stuff. So we did that; we designed this chip for our own internal use. It works very well, and at some point, one of us said, 'Hey, we should probably offer that as a product.' So, it's something that we'd like to offer as a product.

D2P: One of Sigenics' biomedical projects involves an implantable myoelectric sensor (IMES). Can you tell us more about that?

DK: There are two different significant projects that we're involved in that are paid for by the National Institutes of Health, and one of them is the implantable myoelectric sensor. That's been a very long term, ongoing project, and we've had several different NIH grants supporting various stages of development. The whole point of this is to provide a better bionic hand to someone who's had their hand amputated. The current prosthetic hands are capable of doing gripping motions, controlled by the residual muscles in the arm stump. Below your elbow and above your wrist are all the muscles that control your fingers, and there are [many] muscles in there. But so far, the only things that electronic prosthetic hands can do is either grip or rotate the wrist, and that's it—just one at a time, one of those two motions, just two degrees of freedom.

We would like to give somebody far more degrees of freedom, something closer to a natural hand, so that they can reach out and pick up a cup of coffee and sip from it without dropping it. Part of that involves deciphering what's going on with all those different muscles that are still there in their arm, and that's what this sensor is for. It's an implantable device; it's very small—small enough to actually be injected through a large needle. It senses the muscle contractions by being right next to the muscle itself. You can implant a collection of these things, power them through the wireless power link, get back a radio signal that says what the muscles are doing individually, and then use all of that information to control the bionic hand. It's a very cool project.

D2P: I understand you're also working on a retinal stimulator.

DK: There are two of them, and I can tell you something about one of them. We're working closely with a university research lab that is trying to build, basically, a prosthetic device to replace retinal function. So if you get macular degeneration or something like that, you'd have an electronic video camera that would then wire signals into the appropriate part of your brain, replacing the function of the retina and part of the optic nerve. The idea, there again, is to take a pile of electronic function and fit it into a very small space. You don't want to put a giant box of electronics inside, or even on top of, your skull. You want something that's very compact.

D2P: I noticed that one of the RF devices you delivered was tested to spec on equipment built by Sigenics. Do you typically make your own test equipment?

DK: For a lot of cases, we do, especially for things like the DNA chip, for example, which is probably one of the more exotic things that we've done. We frequently end up building electronic assemblies that have some kind of rather peculiar, real world interface. So in order to test it adequately, we have to build something that's a little unconventional. We use off the shelf test equipment as much as possible, but we almost always have to augment it.

D2P: Does that have to do with the custom nature of the parts that you're making?

DK: Exactly, yes. What we want to do is verify that the delivered part really meets the customer's requirements. The customers come to us because they've got requirements having to do with the real world, usually, so it's real world interface stuff that typically ends up having to have some customization.

D2P: Everybody knows about the long running trend toward smaller and smaller devices. Have you seen any other trends that might influence product development in the years to come?

DK: Well, this is really long term and a long shot, but we have our own expertise in biological and medical type electronics. And I don't know if it's just bias because we're already playing in that area, or if it's a real crystal ball, but my own belief is that the area of electronics interfacing to people is going to be a real growth industry at some point, in probably another five to 10 years, as people continue to get more and more attached to things like their cell phones and whatever comes after that. I'm guessing that my children's children are going to want to have built-in video games [laughs].

A while ago, I was at a roundtable discussion about topics like this—you know, 'What's the future of neural electronics?' And I said 'Entertainment is the future of it,' and they all laughed at me, but I actually believe it.

D2P: Do you see a big future for, say, wireless remote monitoring of health conditions, like heart rate monitoring and that type of thing?

DK: Yes, I think that's probably one of the evolution pathways toward the entertainment business end of it. People will find great use in being able to check on heart rate and temperature, and, for all I know, the 'gene sets of the [organisms] that might be invading your bloodstream today.' I don't know how far we could go with that, but being able to have that information as accessible as email and Facebook, and whatever else people happen to be doing, makes sense. Once you're there, then it's not such a huge step to have built-in entertainment systems.

D2P: What's the best part about your job in designing these circuits?

DK: Oh, that's easy, easy, easy. It's seeing the thing work that we've done. I've got the object in my hand, and it's actually doing what it was supposed to do! Love that!

This technical information has been contributed by
Sigenics, Inc.

Click here to find suppliers

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