Ultra Low-power and Fast Wake-up MEMS-based Radios for the IoT 🗓

— Hear how high-Q MEMS resonators can be used to further reduce the power consumption of low-power radios.

Meeting
Irvine, California Map

IEEE OC Section Solid State Circuits Chapter
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Meeting Date: Feb 21, 2019
Time: 6:00 PM Networking & Food; 6:30 PM Presentation
Speaker: Christian Enz, PhD, Swiss Federal Institute of Technology (EPFL)
Location: Irvine, California
Cost: none
RSVP: requested, through website
Event Details: IEEE vTools

Summary: The emergence of the Internet of Things (IoT) poses stringent requirements on the energy consumption and has hence become the primary driver for low-power analog and RF circuit design. Implementation of increasingly complex functions under highly constrained power and area budgets, while circumventing the challenges posed by modern device technologies, makes the design of low-power RF CMOS radios ever more challenging. The power consumption of GHz short-range radios such as the ones used in BTLE has been significantly reduced in the last decade, but seems to level off at a few mW. This is still much too high to allow for continuous-time operation and duty cycling the radio is unavoidable in order to reach the tens of µW power consumption required for a multi-year autonomy. Duty-cycling unavoidably introduces some energy overhead that is wasted during turn-on and turn-off times. On the other hand, since there will be many radios that will share the same media, in order to avoid network congestion, the transmit times have to be made shorter by increasing the peak data rate. This results in the energy overhead becoming dominant. The use of PLL-free synthesizer using an RF MEMS frequency reference enables to minimize the wake-up and shutdown times to a few µs and hence minimize the energy-overhead. We will start with an introduction showing the requirements of IoT nodes with a focus on power consumption. We then will present how high-Q MEMS resonators can be used to further reduce the power consumption of low-power radios. After presenting the main features of high-Q MEMS resonators including bulk acoustic wave (BAW) resonators, we will show how several fundamental RF building blocks can benefit from them. Then we will present possible PLL-free transceiver architectures that take advantage of the very low phase noise and feature very short start-up time to greatly reduce the overhead energy.

Bio: Christian Enz is currently Professor at EPFL and Director of the Institute of Microengineering (IMT) and head of the IC Lab. Until April 2013 he was VP at the Swiss Center for Electronics and Microtechnology (CSEM) in Neuchâtel, Switzerland where he was heading the Integrated and Wireless Systems Division. Prior to joining the CSEM, he was Principal Senior Engineer at Conexant (formerly Rockwell Semiconductor Systems), Newport Beach, CA, where he was responsible for the modeling and characterization of MOS transistors for RF applications. From 1992 to 1997, he was an Assistant Professor at EPFL, working in the field of low-power analog CMOS IC design and device modeling. In 1989 he was one of the founders of Smart Silicon Systems S.A. (S3), where he developed several low-noise and low-power ICs, mainly for high energy physics application at CERN. His technical interests and expertise are in the field of ultra low-power analog and RF IC design, wireless sensor networks and semiconductor device modeling.