Integrated Circuits and Systems Group

ICSG carries out research that spans all major areas of design and design methodology for digital, analog, mixed-signal, and RF CMOS ICs.

Prof. Ian Galton
UCSD
4/2/2012, 11 am, NHB 1.720

Enhancement Techniques for Fractional-N PLL Frequency Synthesizers

Fractional-N phase-locked loops (PLLs) are widely used as RF local oscillators in wireless communication systems. Their performance is critical in such applications, so they are a subject of intensive research. This talk presents recently-developed techniques that mitigate several practical problems in fractional-N PLLs. Phase noise cancellation is presented as a means of relaxing the fundamental tradeoff between fractional-N PLL phase noise and loop bandwidth. A fast-settling adaptive calibration technique is presented that makes phase noise cancellation practical for the low reference frequencies commonly used in wireless communication systems. Various techniques that work in concert to suppress spurious tones are then presented. They include a new type of digital quantizer to replace the digital delta-sigma modulator used in conventional designs, a charge pump offset technique, and a sampled loop filter. A new type of fractional-N PLL with a digital loop filter to reduce circuit area and sensitivity to device leakage and low supply voltage is also presented. Throughout the talk, integrated circuit prototypes are presented in which the various techniques are shown to enable measured state-of-the-art performance.

Prof. Patrick Chiang
Oregon State University
Oct. 28th, 1:30pm, ACE 2.402

Wireless Sensors for the Non-Invasive Monitoring of Aging

Our goal is to develop a wearable sensor microsystem, capturing activity, indoor location, and critical vital signs, for assessing and monitoring independent living of the elderly. In 2009, more than 39.6 million Americans were over the age of 65 (5x more in China), and it is predicted that this number will more than double in the next 20-30 years. In-home monitoring technologies have a great potential to support independent living, by providing continuous critical health status information as well as early diagnosis of cognitive decline and subtle nutritional changes.

In this talk, I will describe the opportunities and challenges that lie in this interdisciplinary research area between sensing, computing, diagnosing, and ultimately, better health.  From a circuit designer’s standpoint, I will describe recent experimental prototypes that may enable a future world using non-invasive wearable sensors: a) indoor location tracking of precise movement/walking for the early detection of cognitive decline; b) near-threshold, robust DSP parallel processor for biomedical sensor signal processing; c) synchronized multi-node wireless body-area networks powered by RF energy harvesting.

Finally, I will discuss recent collaborations with clinicians, such as nutrition specialists (Linus Pauling Institute at OSU) and gerontologists (Oregon Health and Science medical school), attempting to take these captured sensed signals and translate them into healthy aging.

Prof. David Ricketts
Carnegie Mellon University
Oct. 20th, 5:00pm, ACE 2.402

RF devices, circuits & systems: from nanometers to kilometers

In this talk I will discuss three research projects that leverage several areas of physics to solve new problems in radio frequency applications.  The first part of my talk begins in circuits with the millimeter scale and discusses our research aimed at significantly increase the speed, power output and efficiency of mm-wave power amplifiers (PA). Current state-of-the-art Si PAs above 20 GHz suffer from low power-added-efficiency (PAE) and output power, typically < 20% and < 0.5W. I will present our recent results in the development of high PAE (20% – 50%) PAs above 45 GHz using SiGe and 45 nm CMOS and also our work on the development of novel power combiners.  The second part of my talk will present a non-line-of-sight position location system using low frequency magnetoquasistatic fields (l~1 km). Our initial application is in tracking an American football during a game, which is extremely difficult due to the constant obstruction of the ball by the players. We circumvent this problem by using magnetoquasistatic fields, which are not perturbed by the presence of human bodies, to develop a novel tracking system.  I will present our recent research results in collaboration with Disney/ESPN that show the ability to track a football across a football field with approximately 1 ft average error.  In the final part of my talk I will discuss our work using nanoscale devices for RF signal generation and detection.  I will briefly cover our recent work on STM-tip based fabrication of metal-insulator-metal diodes for rectenna applications and our newly evolving work using spin-torque oscillators and diodes in RF applications.