Current Multipliers Improve Processor Performance

Vicor has announced the introduction of Power-on-Package modular current multipliers for high performance, high current, CPU/GPU/ASIC (“XPU”) processors. By freeing up XPU socket pins and eliminating losses associated with delivery of current from the motherboard to the XPU, Vicor’s Power-on-Package solution enables higher current delivery for maximum XPU performance.

In response to the ever-increasing demands of high performance applications–artificial intelligence, machine learning, big data mining—XPU operating currents have risen to Power-on-Package-Enables-Higher-Performance-for-Artificial-Intelligence-Processorshundreds of Amperes. Point-of-Load power architectures in which high current power delivery units are placed close to the XPU, mitigate power distribution losses on the motherboard but do nothing to lessen interconnect challenges between the XPU and the motherboard. With increasing XPU currents, the remaining short distance to the XPU—the “last inch”—consisting of motherboard conductors and interconnects within the XPU socket has become a limiting factor in XPU performance and total system efficiency.

Vicor’s new Power-on-Package Modular Current Multipliers (“MCMs”) fit within the XPU package to expand upon the efficiency, density, and bandwidth advantages of Vicor’s Factorized Power Architecture, already established in 48 V Direct-to-XPU motherboard applications by early adopters. As current multipliers, MCMs mounted on the XPU substrate under the XPU package lid, or outside of it, are driven at a fraction (around 1/64th) of the XPU current from an external Modular Current Driver (MCD). The MCD, located on the motherboard, drives MCMs and accurately regulates the XPU voltage with high bandwidth and low noise. The solution profiled today, consisting of two MCMs and one MCD, enables delivery of up to 320 A of continuous current to the XPU, with peak current capability of 640 A.

With MCMs mounted directly to the XPU substrate, the XPU current delivered by the MCMs does not traverse the XPU socket. And, because the MCD drives MCMs at a low current, power from the MCD can be efficiently routed to MCMs reducing interconnect losses by 10X even though 90% of the XPU pins typically required for power delivery are reclaimed for expanded I/O functionality. Additional benefits include a simplified motherboard design and a substantial reduction in the minimum bypass capacitance required to keep the XPU within its voltage limits.

Multiple MCMs may be operated in parallel for increased current capability. The small (32mm x 8mm x 2.75mm) package and low noise characteristics of the MCM make it suitable for co-packaging with noise-sensitive, high performance ASICs, GPUs and CPUs. Operating temperature range is -40°C to +125°C. These devices represent the first in a portfolio of Power-on-Package solutions scalable to various XPU needs.

Vicor |

Q&A: Scott Garman, Technical Evangelist

Scott Garman is more than just a Linux software engineer. He is also heavily involved with the Yocto Project, an open-source collaboration that provides tools for the embedded Linux industry. In 2013, Scott helped Intel launch the MinnowBoard, the company’s first open-hardware SBC. —Nan Price, Associate Editor

Scott Garman

Scott Garman

NAN: Describe your current position at Intel. What types of projects have you developed?

SCOTT: I’ve worked at Intel’s Open Source Technology Center for just about four years. I began as an embedded Linux software engineer working on the Yocto Project and within the last year, I moved into a technical evangelism role representing Intel’s involvement with the MinnowBoard.

Before working at Intel, my background was in developing audio products based on embedded Linux for both consumer and industrial markets. I also started my career as a Linux system administrator in academic computing for a particle physics group.

Scott was involved with an Intel MinnowBoard robotics and computer vision demo, which took place at LinuxCon Japan in May 2013.

Scott was involved with an Intel MinnowBoard robotics and computer vision demo, which took place at LinuxCon Japan in May 2013.

I’m definitely a generalist when it comes to working with Linux. I tend to bounce around between things that don’t always get the attention they need, whether it is security, developer training, or community outreach.

More specifically, I’ve developed and maintained parallel computing clusters, created sound-level management systems used at concert stadiums, worked on multi-room home audio media servers and touchscreen control systems, dug into the dark areas of the Autotools and embedded Linux build systems, and developed fun conference demos involving robotics and computer vision. I feel very fortunate to be involved with embedded Linux at this point in history—these are very exciting times!

Scott is shown working on an Intel MinnowBoard demo, which was built around an OWI Robotic Arm.

Scott is shown working on an Intel MinnowBoard demo, which was built around an OWI Robotic Arm.

NAN: Can you tell us a little more about your involvement with the Yocto Project (

SCOTT: The Yocto Project is an effort to reduce the amount of fragmentation in the embedded Linux industry. It is centered on the OpenEmbedded build system, which offers a tremendous amount of flexibility in how you can create embedded Linux distros. It gives you the ability to customize nearly every policy of your embedded Linux system, such as which compiler optimizations you want or which binary package format you need to use. Its killer feature is a layer-based architecture that makes it easy to reuse your code to develop embedded applications that can run on multiple hardware platforms by just swapping out the board support package (BSP) layer and issuing a rebuild command.

New releases of the build system come out twice a year, in April and October.

Here, the OWI Robotic Arm is being assembled.

Here, the OWI Robotic Arm is being assembled.

I’ve maintained various user space recipes (i.e., software components) within OpenEmbedded (e.g., sudo, openssh, etc.). I’ve also made various improvements to our emulation environment, which enables you to run QEMU and test your Linux images without having to install it on hardware.

I created the first version of a security tracking system to monitor Common Vulnerabilities and Exposures (CVE) reports that are relevant to recipes we maintain. I also developed training materials for new developers getting started with the Yocto Project, including a very popular introductory screencast “Getting Started with the Yocto Project—New Developer Screencast Tutorial

NAN: Intel recently introduced the MinnowBoard SBC. Describe the board’s components and uses.

SCOTT: The MinnowBoard is based on Intel’s Queens Bay platform, which pairs a Tunnel Creek Atom CPU (the E640 running at 1 GHz) with the Topcliff Platform controller hub. The board has 1 GB of RAM and includes PCI Express, which powers our SATA disk support and gigabit Ethernet. It’s an SBC that’s well suited for embedded applications that can use that extra CPU and especially I/O performance.

Scott doesn’t have a dedicated workbench or garage. He says he tends to just clear off his desk, lay down some cardboard, and work on things such as the Trippy RGB Waves Kit, which is shown.

Scott doesn’t have a dedicated workbench or garage. He says he tends to just clear off his desk, lay down some cardboard, and work on things such as the Trippy RGB Waves Kit, which is shown.

The MinnowBoard also has the embedded bus standards you’d expect, including GPIO, I2C, SPI, and even CAN (used in automotive applications) support. We have an expansion connector on the board where we route these buses, as well as two lanes of PCI Express for custom high-speed I/O expansion.

There are countless things you can do with MinnowBoard, but I’ve found it is especially well suited for projects where you want to combine embedded hardware with computing applications that benefit from higher performance (e.g., robots that use computer vision, as a central hub for home automation projects, networked video streaming appliances, etc.).

And of course it’s open hardware, which means the schematics, Gerber files, and other design files are available under a Creative Commons license. This makes it attractive for companies that want to customize the board for a commercial product; educational environments, where students can learn how boards like this are designed; or for those who want an open environment to interface their hardware projects.

I created a MinnowBoard embedded Linux board demo involving an OWI Robotic Arm. You can watch a YouTube video to see how it works.

NAN: What compelled Intel to make the MinnowBoard open hardware?

SCOTT: The main motivation for the MinnowBoard was to create an affordable Atom-based development platform for the Yocto Project. We also felt it was a great opportunity to try to release the board’s design as open hardware. It was exciting to be part of this, because the MinnowBoard is the first Atom-based embedded board to be released as open hardware and reach the market in volume.

Open hardware enables our customers to take the design and build on it in ways we couldn’t anticipate. It’s a concept that is gaining traction within Intel, as can be seen with the announcement of Intel’s open-hardware Galileo project.

NAN: What types of personal projects are you working on?

SCOTT: I’ve recently gone on an electronics kit-building binge. Just getting some practice again with my soldering iron with a well-paced project is a meditative and restorative activity for me.

Scott’s Blinky POV Kit is shown. “I don’t know what I’d do without my PanaVise Jr. [vise] and some alligator clips,” he said.

Scott’s Blinky POV Kit is shown. “I don’t know what I’d do without my PanaVise Jr. [vise] and some alligator clips,” he said.

I worked on one project, the Trippy RGB Waves Kit, which includes an RGB LED and is controlled by a microcontroller. It also has an IR sensor that is intended to detect when you wave your hand over it. This can be used to trigger some behavior of the RGB LED (e.g., cycling the colors). Another project, the Blinky POV Kit, is a row of LEDs that can be programmed to create simple text or logos when you wave the device around, using image persistence.

Below is a completed JeeNode v6 Kit Scott built one weekend.

Below is a completed JeeNode v6 Kit Scott built one weekend.

My current project is to add some wireless sensors around my home, including temperature sensors and a homebrew security system to monitor when doors get opened using 915-MHz JeeNodes. The JeeNode is a microcontroller paired with a low-power RF transceiver, which is useful for home-automation projects and sensor networks. Of course the central server for collating and reporting sensor data will be a MinnowBoard.

NAN: Tell us about your involvement in the Portland, OR, open-source developer community.

SCOTT: Portland has an amazing community of open-source developers. There is an especially strong community of web application developers, but more people are hacking on hardware nowadays, too. It’s a very social community and we have multiple nights per week where you can show up at a bar and hack on things with people.

This photo was taken in the Open Source Bridge hacker lounge, where people socialize and collaborate on projects. Here someone brought a brainwave-control game. The players are wearing electroencephalography (EEG) readers, which are strapped to their heads. The goal of the game is to use biofeedback to move the floating ball to your opponent’s side of the board.

This photo was taken in the Open Source Bridge hacker lounge, where people socialize and collaborate on projects. Here someone brought a brainwave-control game. The players are wearing electroencephalography (EEG) readers, which are strapped to their heads. The goal of the game is to use biofeedback to move the floating ball to your opponent’s side of the board.

I’d say it’s a novelty if I wasn’t so used to it already—walking into a bar or coffee shop and joining a cluster of friendly people, all with their laptops open. We have coworking spaces, such as Collective Agency, and hackerspaces, such as BrainSilo and Flux (a hackerspace focused on creating a welcoming space for women).

Take a look at Calagator to catch a glimpse of all the open-source and entrepreneurial activity going on in Portland. There are often multiple events going on every night of the week. Calagator itself is a Ruby on Rails application that was frequently developed at the bar gatherings I referred to earlier. We also have technical conferences ranging from the professional OSCON to the more grassroots and intimate Open Source Bridge.

I would unequivocally state that moving to Portland was one of the best things I did for developing a career working with open-source technologies, and in my case, on open-source projects.

Q&A: Peter Lomas – Raspberry Pi: One Year Later, 1 Million Sold

Peter Lomas

Clemens Valens, Editor-in-Chief of Elektor Online and head of Elektor Labs, caught up with Peter Lomas, hardware designer for the Raspberry Pi single-board computer, earlier this year at the Embedded World 2013 trade show in Nuremberg, Germany. This is a longer version of an interview with Lomas published in Elektor’s May 2013 issue. The Lomas interview provided a one-year update on the rapid growth of interest in the Raspberry Pi since Elektor’s April 2012 interview with Eben Upton, one of the founders and trustees of the Raspberry Pi Foundation. The UK-based charitable foundation developed the inexpensive, credit card-sized computer to encourage the study of basic computer science in schools. In early 2012, the Raspberry Pi’s first production batches were arriving. Since then, more than 1 million boards have been sold.

CLEMENS: Raspberry Pi, the phenomena. It is quite amazing what happened.

PETER: It is, and lots of people keep asking me, why has Raspberry Pi done what it has done, what makes it different? I think it’s something we’ve really been trying to grasp. The first thing that happened with Raspberry Pi, which I think is important, is that we had one of our very first prototypes on a UK blog for one of the BBC correspondents, Rory Cellan-Jones, and they made a little video, a YouTube video, and that got 600,000 hits. So I guess that if you look at it from one aspect, that created a viral marketing, a very viral marketing campaign for Raspberry Pi. The other I think, the name, Raspberry Pi was key. And the logo that Paul Beach did for us is absolutely key because it has become iconic.

CLEMENS: Yes, it’s very recognizable.

PETER: Very recognizable. If I show you that, you know exactly what it is, in the electronics circle. So I think the brand has been very important. But you know, we shouldn’t forget the amount of work that Liz Upton’s been doing with the blogs and on our website, keeping people informed about what we’re doing. Then, I think we’ve got the fact we are a charity… that we are focused on the education of computing and electronics and that’s our motive—not actually to make boards and to make money except to fund the foundation.

CLEMENS: I looked at the Raspberry Pi website, and it doesn’t look easy to me. You target education, children, and on the website it’s hard to find what Raspberry Pi exactly is. It’s not really explained. You have to know it. There are several distributions, so you have to know Linux and you have to program in Python.

PETER: Well, that’s true and, in a weird way, that’s part of its success, because you actually have to be active. In order to do something with Pi, you can’t just get it out of a shiny box, put it on the desk and press “on.” You have to do some mental work. You have to figure some things out. Now, I actually think that there’s a bit of a benefit there, because when it actually works, you have some achievement. You’ve done something. Not “we’ve done something.” You’ve done it personally, and there is a gratification from doing it.

CLEMENS: But it’s not the easiest platform.

PETER: No, but with our educational proposition, the whole object now is to package that up in easier-to-use bundles. We can make the SD card boot straight to Scratch (a website project and simple programming language developed at the Massachusetts Institute of Technology Media Lab), so Linux becomes temporarily invisible, and there’s a set of worksheets and instructions. But we’re never going to take away, hopefully, the fact that you have to put your wires in, and I do think that is part of the importance and the attraction of it.

CLEMENS: Because of all these layers of complexity and having to program it in English (Python is in English), for the non-English population it is yet another hurdle. That’s why Arduino was so successful; they made the programming really easy. They had cheap hardware but also a way to easily program it.

PETER: There’s no doubt Arduino is a brilliant product. You are right, it enables people to get to what I call “Hello World” very easily. But, in fact, on a Raspberry Pi, after you’ve made those connections and plugged the card in, you can get to an equivalent “Hello World.” But ours is the Scratch cat. Once you’ve moved the Scratch cat, you can go in a few different directions: you can move it some more, or you can use Scratch with an I/O interface to make an LED light up or you can press a button to make the Scratch cat move. There are endless directions you can go. I’ve found, and I think Eben has similarly experienced, that kids just get it. As long as you don’t make it too complicated, the kids just get it. It’s the adults who have more problems.

CLEMENS: I saw that there are at least three different distributions for the boards. So what are the differences between the three? Why isn’t there just one?

PETER: Well, they all offer subtly different features. The whole idea was to make Raspberry Pi as an undergraduate tool. You give it to Cambridge University, hopefully Manchester University, and undergraduates can view the science before they start it. They have the summer. They can work on it, come back, and say: “Look, I did this on this board.” That’s where it all started.

CLEMENS: OK. So, you were already on quite a high level.

PETER: Well we were on a high level, that’s true. We were on a high level, so Scratch wouldn’t have been on the agenda. It was really just Python—that’s actually where the Pi comes from.
What has really happened is that we’ve developed this community and this ecosystem around Pi. So we have to be able to support the, if you like, “different roots” of people wanting to use Pi. Now we’ve got the RISC OS that you can use. And people are even doing bare-metal programming. If we just gave one distribution, I guess we’re closing it up. I fully approve of having different distributions.

CLEMENS: From the website, it’s not clear to me what is different in these distributions. For the first one, it is written: “If you’re just starting out.”

PETER: I think maybe we do need to put some more material in there to explain to people the difference. I have to explain: I’m the hardware guy. I’m the guy who sat there connecting the tracks up, connecting the components up. My expertise with the operating systems, with the distributions that we have, is really limited to the graphical interface because that’s what I use day in, day out.

CLEMENS: Once you have chosen your distribution and you want to control an LED, you have to open a driver or something, I suppose?

PETER: Well, you’ve got the library; you just have to make a library call. Again, it’s not easy. You have to go and find the libraries and you have to download them. Which is where things such as the Pi-Face (add-on board) come in, because that comes with an interactive library that will go onto Scratch. And you’ve got the Gertboard (another extension board) and that comes with the libraries to drive it and some tutorial examples and then you can wind that back to just the bare metal interface on the GPIOs.

CLEMENS: So the simplicity is now coming from the add-on boards?

PETER: Some of the add-on boards can make it simpler, where they give you the switches and they give you the LEDs. You don’t need to do any wiring. My view is that I’m trying to make it like an onion: You can start with the surface and you can do something, and then you can peel away the layers. The more interested you get, the more layers you can peel away and the more different directions you can go (in what you do with it). You must have seen the diverse things that can be done.

CLEMENS: I’ve looked at some projects. I was surprised by the number of media centers. That’s how RS Components (which distributes the Raspberry Pi) is promoting the board. Aren’t you disappointed with that? It seems to be, for a lot of people, a cheap platform to do a Linux application on. They just want to have a media center.

PETER: I know exactly what you mean. And I suppose I should be disappointed that some people buy it, they make it into a media center, and that’s all it does. But I think if only 5% or 10% of those people who make it into a media center will think: “Well, that was easy, maybe I’ll get another and see if I can do something else with it,” then it’s a success.

CLEMENS: It would be an enabler.

PETER: Getting the technology in front of people is the first problem. Getting the “Hello World” so they’ve got a sense of achievement is the second problem. Then turning them over from doing that to “Okay, well what if I try and do this?”  then that’s  Nirvana. Certainly for the kids that’s crucial, because we’re changing them from doing what they’re told, to start doing things that they think they might be able to do—and trying it. That makes them into engineers.

CLEMENS: Let’s move on to the board’s hardware.

PETER: Sure.

CLEMENS: So, you chose a Broadcom processor. Because Eben worked at Broadcom?

PETER: He still works within Broadcom. It would be hard for me to argue that that wasn’t an influence on the decision, because Eben said: “Oh look, here’s the bright shiny chip. It can do all the things that we want, why wouldn’t we use it?” The decision we made is we nailed our credentials and our reputations to the website by saying it will cost $35—it will cost $25 for the basic one. And there was no way on Earth any of us were going to go back on that… We had a spreadsheet, the basic numbers looked plausible, we just had to do a lot of work to chop it down—to hone it, to get it tight so it would actually meet the prices. So, I think if we’d gone another way, like maybe with Samsung, that would have blown the budget.

CLEMENS: Did Broadcom help in any way to make this possible?

PETER: Every semiconductor manufacturer helped the project by making the chips available. Also, the price point of the chips is important. I think some of the people who helped us took an educated gamble and gave us good pricing from day one. Because the big problem you get with trying to bootstrap any project, is that if you don’t know what your volume is going to be. You have to be conservative.

So, initially, we priced for a thousand boards, but quickly we priced for 20,000 boards, but nowhere in our wildest dreams did we think we were going to get to a 200,000-board requirement on launch day and be so tantalizingly close to selling a million after our first year. So that’s helped in a lot of ways, because obviously it’s driven the price of all the components down. I’m not going to pretend it doesn’t please the vendors of the components that had faith in us from day one, because they’ve obviously made some money out of it.

We always had the rationale that we had to have a sustainable model where the foundation, our community that is buying the boards, and our suppliers were all making a living and could feed themselves. It would have been a total disaster if someone such as Broadcom had said: “Tell you what guys, let’s give you the processors. We’ll give you the first 20,000.” And so, we could have provided all sorts of extra bells and whistles to the design. Then, when we would have sold these 20,000 boards, we’re going to raise the price of everything by $12. That would’ve been the end of Raspberry Pi.

CLEMENS: If Eben and the others had not worked for Broadcom…

PETER: Would we have used a different chip? Well, I sort of speculated about this and I went around and had a look and, at the time for the price point, we couldn’t find anything that would’ve met our requirements as well as that chip. So I was comfortable that was the one that would allow us to get to where we wanted to be, and I think the big key crunch for that was the high-definition multimedia interface (HDMI). From a technical point of view, one of the challenges we had was getting the breakout under the BGA, because blind and buried vias on PCBs are very expensive.

CLEMENS: How many layers is the board?

PETER: Six, which is a pretty bog-standard layer count. The only little trick that we used was to put blind vias only on layers one and two—so we had an extra drilling stage—but only one bonding stage. So that added $0.02 onto the cost of the board. But, because the next layer down was a ground plane, it meant that a lot of the connections that come out of the Broadcom processor just go down one layer. And that meant that I could have space underneath to route other things and actually make it all happen.

CLEMENS: Don’t they have guidelines at Broadcom?

PETER: Oh, they do have guidelines! Use blind and buried vias or vias in pads. Our first prototype was all singing, all dancing, but it would have cost $100 to $110 to manufacture. So we got the machete out and started hacking down all the things that we didn’t need. So you’ve got all the functionality that you want. You can get the performance that you want, you can get the compliance, but it’s got nothing extra.

CLEMENS: Have you been thinking about the future of Raspberry Pi?

PETER: Well, yeah… In our industry, you know, Moore’s law guarantees that everything is old-hat in two years’ time. So we’re thinking about it, but that’s all we’re doing. We’re trying to improve our educational release. I mean, let’s face it, I’m not going to pretend that the Raspberry Pi is perfect. We only made one modification to the board from design to release. We’ve only made some minor modifications under the V2 release. Some of that is to fix some anomalies, some of that was also to help our new manufacturing partner, Sony (in Pencoed, Wales), take it. Their process needed some slight changes to the board to make it easier to manufacture.

CLEMENS: About the original idea of Raspberry Pi, the educational thing. I had a look at the forum and there are lots of forums about technical details, quite a lot of questions and topics about start-up problems. But the educational forum is pretty small.

PETER: You’re right. You’re absolutely right. A lot of that work has been going on slowly and carefully in the background. To be completely honest with you, we were caught on the hub with the interest with Raspberry Pi, and so I’ve certainly spent the last 12 months making sure that we can deliver the product to our community so that they can develop with it and perhaps talk a little bit about our educational goals. But we’re absolutely refocusing on that.

CLEMENS: First, get the hardware into people’s hands and then focus on the education.

PETER: Exactly. And of course, we’ve also released the first computers in schools as manual teaching tools. But also we’ve got Clive, who is a full-time employee helping with the educational deployment. And it’s great that we’ve had all this support (from Google Giving) to get 15,000 kits into schools. I won’t pretend we don’t have a lot of work to do but, I think of where we were a year ago, just still trying to launch.

CLEMENS: It all went really fast.

PETER: Oh yes, it’s gone like a rocket!

CLEMENS: Have you personally learned something valuable from it?

PETER: Well, I’ve learned lots of things. I think the most valuable, maybe not a lesson, but a reinforcement of something I already thought, is that education doesn’t just exist in the classroom. It exists all around us. The opportunity to learn and the opportunity to teach exists every day in almost every aspect in what we do. You know, there are people who spend their lives trying to keep every secret, keep everything to themselves. But there are also people who just give. And I’ve met so many people who are just givers. I suppose I’ve learned there is a whole new system of education that goes on outside of the standard curriculum that helps people do what they want to do.

Editor’s Note: Interview by Clemens Valens, Transcription by Joshua Walbey.


  • Embedded Linux Wiki, “RPi Gertboard,”
  • W. Hettinga, “What Are You Doing? The Raspberry Pi $25 Computer,” Elektor April 2012.
  • Massachusetts Institute of Technology Media Lab, “Scratch,”
  • University of Manchester School of Computer Science, Projects Using Raspberry Pi, “Pi-Face Digital Interface,”


The Future of Very Large-Scale Integration (VLSI) Technology

The historical growth of IC computing power has profoundly changed the way we create, process, communicate, and store information. The engine of this phenomenal growth is the ability to shrink transistor dimensions every few years. This trend, known as Moore’s law, has continued for the past 50 years. The predicted demise of Moore’s law has been repeatedly proven wrong thanks to technological breakthroughs (e.g., optical resolution enhancement techniques, high-k metal gates, multi-gate transistors, fully depleted ultra-thin body technology, and 3-D wafer stacking). However, it is projected that in one or two decades, transistor dimensions will reach a point where it will become uneconomical to shrink them any further, which will eventually result in the end of the CMOS scaling roadmap. This essay discusses the potential and limitations of several post-CMOS candidates currently being pursued by the device community.

Steep transistors: The ability to scale a transistor’s supply voltage is determined by the minimum voltage required to switch the device between an on- and an off-state. The sub-threshold slope (SS) is the measure used to indicate this property. For instance, a smaller SS means the transistor can be turned on using a smaller supply voltage while meeting the same off current. For MOSFETs, the SS has to be greater than ln(10) × kT/q where k is the Boltzmann constant, T is the absolute temperature, and q is the electron charge. This fundamental constraint arises from the thermionic nature of the MOSFET conduction mechanism and leads to a fundamental power/performance tradeoff, which could be overcome if SS values significantly lower than the theoretical 60-mV/decade limit could be achieved. Many device types have been proposed that could produce steep SS values, including tunneling field-effect transistors (TFETs), nanoelectromechanical system (NEMS) devices, ferroelectric-gate FETs, and impact ionization MOSFETs. Several recent papers have reported experimental observation of SS values in TFETs as low as 40 mV/decade at room temperature. These so-called “steep” devices’ main limitations are their low mobility, asymmetric drive current, bias dependent SS, and larger statistical variations in comparison to traditional MOSFETs.

Spin devices: Spintronics is a technology that utilizes nano magnets’ spin direction as the state variable. Spintronics has unique properties over CMOS, including nonvolatility, lower device count, and the potential for non-Boolean computing architectures. Spintronics devices’ nonvolatility enables instant processor wake-up and power-down that could dramatically reduce the static power consumption. Furthermore, it can enable novel processor-in-memory or logic-in-memory architectures that are not possible with silicon technology. Although in its infancy, research in spintronics has been gaining momentum over the past decade, as these devices could potentially overcome the power bottleneck of CMOS scaling by offering a completely new computing paradigm. In recent years, progress has been made toward demonstration of various post-CMOS spintronic devices including all-spin logic, spin wave devices, domain wall magnets for logic applications, and spin transfer torque magnetoresistive RAM (STT-MRAM) and spin-Hall torque (SHT) MRAM for memory applications. However, for spintronics technology to become a viable post-CMOS device platform, researchers must find ways to eliminate the transistors required to drive the clock and power supply signals. Otherwise, the performance will always be limited by CMOS technology. Other remaining challenges for spintronics devices include their relatively high active power, short interconnect distance, and complex fabrication process.

Flexible electronics: Distributed large area (cm2-to-m2) electronic systems based on flexible thin-film-transistor (TFT) technology are drawing much attention due to unique properties such as mechanical conformability, low temperature processability, large area coverage, and low fabrication costs. Various forms of flexible TFTs can either enable applications that were not achievable using traditional silicon based technology, or surpass them in terms of cost per area. Flexible electronics cannot match the performance of silicon-based ICs due to the low carrier mobility. Instead, this technology is meant to complement them by enabling distributed sensor systems over a large area with moderate performance (less than 1 MHz). Development of inkjet or roll-to-roll printing techniques for flexible TFTs is underway for low-cost manufacturing, making product-level implementations feasible. Despite these encouraging new developments, the low mobility and high sensitivity to processing parameters present major fabrication challenges for realizing flexible electronic systems.

CMOS scaling is coming to an end, but no single technology has emerged as a clear successor to silicon. The urgent need for post-CMOS alternatives will continue to drive high-risk, high-payoff research on novel device technologies. Replicating silicon’s success might sound like a pipe dream. But with the world’s best and brightest minds at work, we have reasons to be optimistic.

Author’s Note: I’d like to acknowledge the work of PhD students Ayan Paul and Jongyeon Kim.

Embedded Sensor Innovation at MIT

During his June 5 keynote address at they 2013 Sensors Expo in Chicago, Joseph Paradiso presented details about some of the innovative embedded sensor-related projects at the MIT Media Lab, where he is the  Director of the Responsive Environments Group. The projects he described ranged from innovative ubiquitous computing installations for monitoring building utilities to a small sensor network that transmits real-time data from a peat bog in rural Massachusetts. Below I detail a few of the projects Paradiso covered in his speech.


Managed by the Responsive Enviroments group, the DoppelLab is a virtual environment that uses Unity 3D to present real-time data from numerous sensors in MIT Media Lab complex.

The MIT Responsive Environments Group’s DoppleLab

Paradiso explained that the system gathers real-time information and presents it via an interactive browser. Users can monitor room temperature, humidity data, RFID badge movement, and even someone’s Tweets has he moves throughout the complex.

Living Observatory

Paradiso demoed the Living Observatory project, which comprises numerous sensor nodes installed in a peat bog near Plymouth, MA. In addition to transmitting audio from the bog, the installation also logs data such as temperature, humidity, light, barometric pressure, and radio signal strength. The data logs are posted on the project site, where you can also listen to the audio transmission.

The Living Observatory (Source:


The GesturesEverywhere project provides a real-time data stream about human activity levels within the MIT Media Lab. It provides the following data and more:

  • Activity Level: you can see the Media Labs activity level over a seven-day period.
  • Presence Data: you can see the location of ID tags as people move in the building

The following video is a tracking demo posted on the project site.

The aforementioned projects are just a few of the many cutting-edge developments at the MIT Media Lab. Paradiso said the projects show how far ubiquitous computing technology has come. And they provide a glimpse into the future. For instance, these technologies lend themselves to a variety of building-, environment-, and comfort-related applications.

“In the early days of ubiquitous computing, it was all healthcare,” Paradiso said. “The next frontier is obviously energy.”