Upcoming Seminars

  • Title : VLSI Architectures for Communications and Signal Processing
    Speaker: Dr. Kiran Gunnam, Violin Memory
  • Date: Friday, May 2nd, 2:30pm-4:30pm, 750 Interschool Lab, CEPSR


    Dr. Joseph Shor,
    Intel Yakum

    Monday, Feb 17th, 12:00pm-1:00pm
    825 Mudd

    Compact Thermal Sensors in Intel Processors from 90nm to 22nm

    Temperature sensing and regulation in microprocessors are important for power management and have a direct influence on power/performance. When the chip gets too hot, its frequency gets lowered in a process called throttling, in order to prevent it from exceeding the maximum reliable operating point. As temperature is lowered, the frequency of the chip can degrade because of the ITD effect (Inverse Temperature Dependence). In this case, information from the thermal sensor is used to raise the supply voltage to maintain performance. The thermal sensor is also used for fan regulation and prevents the chip from burning itself up in thermal runaway. In the older chips, there was a single core, so it was sufficient to have one or two thermal sensors per IC, and the power and area were not very important. Since the industry shifted to multicore, there can be as many as 25 sensors per chip, so their area and power have become substantial. In addition, analog circuits tend to have very poor scaling between process generations, or even reverse scale. In the Nehalem generation the thermal sensors occupied more than 1% of the overall die area, and consumed > 200mW, so there was much motivation to scale them down. In our group in Yakum, Israel, we have developed compact and power-efficient thermal sensors. Using novel analog architectures and circuit techniques the area and power were scaled by > 10X in the same process generation. The level of scaling in analog is virtually unheard of. In the Sandy-Bridge processor, we implemented an NMOS based sensor, which measured the temperature dependence of threshold voltage (Vt) and mobility (Mu) and output a temperature-dependent frequency. In addition, we also developed a very compact diode-based thermal sensor which used a band-gap reference to generate a temperature-dependent voltage, which was measured using a frequency-based analog-to-digital converter. The diode sensor is considered more reliable than the NMOS based design since Vt and Mu change during the process evolution. The 22nm sensor was one of the world's first analog circuits reported at this process node. These sensors have been benchmarked as the smallest IC thermal sensors in the art, with sizes < 0.006 mm2. They also have a very fast sampling speed (> 5kS/sec), which enable them to capture fast thermal transients on the processor. The designs are very robust and can be manufactured with > 99.9% yield. The evolution of these sensors from 90nm down to 22nm will be discussed, along with some of challenges inherent in designing analog circuits in the noisy, pure-digital environment of a microprocessor.

    PhD in Electrical Engineering from Columbia University, 1993. BA in Physics, Queens College, 1986. Shor has published more than 50 papers in refereed Journals and Conference Proceedings in the areas of Analog Circuit Design and Device Physics. He holds 35 issued patents and several pending patents. Since 2004, he has been at Intel Corporation, where he is presently a Principal Engineer, and head of the Analog Team at Intel Yakum in Israel. Between 1999-2004, he worked at Saifun Semiconductor as a Staff Engineer where he established the analog activities for Flash and EEPROM NROM memories. From 1994-1999, he was a Senior Analog Designer at Motorola Semiconductor in the DSP Division. From 1988-1994, he was a Senior Research Scientist at Kulite Semiconductor, where he developed processes and devices for Silicon Carbide and Diamond Microsensors. His present interests include Switching and Linear Voltage Regulators, thermal Sensors, reference circuits, PLLs , IO circuits, and low voltage/power analog circuits. He is also interested in microsensor design, physics and applications. He is an IEEE Senior Member and a member of the ISSCC Technical Program committee.

    Dr. Alessandro Piovaccari,
    Silicon Labs

    Friday, March 14th, 2:00pm-3:00pm
    227 Mudd

    A simple method to calculate the power spectrum of distorted wide-band signals

    The correct analysis of distortion products is one of the most important aspects in the design of low-power low-cost communication devices. There is a fundamental trade off between cost, power and dynamic range of the system. More precisely, the lower and upper boundaries of the dynamic range are determined respectively by the linearity and noise performance of the system, which in turn are determined by the technology choice, architecture and power consumption of the system itself. As an application example, a typical RF signal receiver is composed by a cascade of blocks performing operation of filtering, amplifying, frequency translation and data conversion. An almost century-long of literature on this topic has shown that for a given performance specification, the optimal design in terms of power consumption and cost is determined by a correct distribution of gain, filtering, and noise and distortion performance among the various blocks constituting the receiving chain. Another very important application is the determination of spurious spectral emission of a transmission system. Spectrum scarcity and pollution due to older standard (like the TV system) has forced government controlled agencies (FCC, ETSI, …) to define transmission regulations, including strict spectrum emission masks. This fact ultimately results on the architectural choice of the power amplifier of the transmitter, and the consequent trade-off between its linearity and power efficiency. As of today, the determination of the distortion products in weakly non-linear systems has been mainly relying on simplified sinusoidal analysis. While this analysis has the advantage of being simple enough to be usable in hand calculation or in spreadsheets, it produces good predictions results only for narrowband signals containing a strong carrier (FM, AM, …), but it is inadequate to predict the distortion effect on wide-band signals that have statistics similar to band-pass noise, like OFDM signals used in digital television (DTV) and Wireless Local Access Networks (WLAN). Several analysis has been performed in literature during the last 50 years to overcome the limitation of simple sinusoidal distortion analysis, but the math involved is generally quite complex and because of the wide availability of CAD and computation tools, system designers generally prefer to rely on time-domain simulations. This work, present a method to calculate the exact effect of distortion on wide-band signal signal that have Gaussian-like characteristics, including the determination of the exact power of the distortion products, and the prediction of effects like spectral corruption and spectral regrowth, that are not predictable by traditional sinusoidal analysis. It is important to note that, even if this method is based on results of advanced mathematics (Hermite polynomials), its results are simple enough to be usable in hand calculations, similar to sinusoidal distortion analysis. Moreover, the method can be use to calculate the exact power spectrum of the output of a non-linear system when a band-pass signal of non-negligible bandwidth and approximated by a Gaussian wide-sense stationary (WSS) random process is applied to its input, using simple matrix mathematics and without the need of a time-domain simulation.

    Dr. Alessandro Piovaccari received the Laurea and Ph.D. degrees in electronic engineering from the University of Bologna, Bologna, Italy, in 1993 and 1998, respectively and a Post-Master's Advanced Certificate with Honors in electrical engineering from Johns-Hopkins University, Baltimore, MD, in 2002. In 1997, he joined Tanner Research in Pasadena, CA as a Research Scientist in where he worked on the development of a CMOS image sensors with embedded motion detection. From 1998 to 2003 he has been part of the design services team as of Cadence Design Systems in Columbia, MD where he worked on CMOS RFICs for wireless communications and in Cary, NC where he managed the high-speed SerDes development. Since 2003, he has been part of Silicon Laboratories in Austin, TX where he contributed to the architecture definition and IC design of the single-chip FM radio, which as today sold more than 1.2 billion devices. He also managed the development and co-architected the single-chip TV tuner, currently employed in more that 55% of the TV sold world-wide. He currently holds a VP of Engineering position and he's responsible for the development of the MCU, wireless, and audio/video broadcast products. He's the author of 9 papers and 31 patents (20 currently issued). Dr. Piovaccari is a Senior Member of IEEE and Full Member of AES. He is part of the Technical Program Committee of CICC, where he also served as chair of the Analog Subcommittee. He has been reviewer for IEEE conference and journal including CICC, ISCAS, JSSC, MTT and CAS.

    Dr. E.A.M.Klumperink
    Univ. of Twente

    Monday, March 31st, 12:00pm-1:00pm
    Room 825, Mudd

    Cognitive Radio Transceiver Chips (SSCS Distinguished Lecture)

    A Cognitive Radio transceiver senses its radio environment and adaptively utilizes free parts of the radio spectrum. CMOS IC-technology is the mainstream technology to implement smart signal processing and for reasons of cost and size it is attractive to also integrate the radio frequency (RF) hardware in CMOS. This lecture discusses radio transceiver ICs designed for cognitive radio applications, with focus on analog RF. Cognitive radio asks for new functionality, e.g. spectrum sensing and more agility in the radio transmitter and flexibility in the receiver. Moreover, the technical requirements on the building blocks are more challenging than for traditional single standard applications, e.g. in bandwidth, programmability, sensing sensitivity, blocker tolerance, linearity and spurious emissions. Circuit ideas that address these challenges will be discussed, and examples of chips and their achieved performance will be given.

    Eric Klumperink received his PhD from Twente University in Enschede, The Netherlands, in 1997. He is currently an Associate Professor at the same university where he teaches Analog and RF CMOS IC Design and guides research projects focusing on Cognitive Radio, Software Defined Radio and Beamforming. Eric served as Associate Editor for TCAS-I and II, and for the Journal of Solid-State Circuits. He is a technical program committee member of ISSCC and RFIC and is Respected Lecturer for IEEE. He holds several patents, authored and co-authored more than 150 international refereed journal and conference papers, and is a co-recipient of the ISSCC 2002 and the ISSCC 2009 "Van Vessem Outstanding Paper Award".

    Dr. Aaron Buchwald
    Entropic Communications

    Friday, April 4th, 2:00pm-3:00pm
    Room 227, MUDD

    Challenges of Calibrated Time-Interleaved High-Speed ADCs

    The dream of moving the ADC of a communication receiver all the way to the antenna is fast becoming a reality. Recent ADCs that take advantage of time-interleaving and rely heavily on calibration enable new receiver architectures where the entire spectrum is digitized while all channelization and demodulation is done in the digital domain. Such systems that are "RF-to-Digital" have many advantages. However, the design of the requisite ADC remains a challenge to achieve wide-bandwidth and high dynamic-range at very low power. This talk introduces key concepts of calibrated time-interleaved ADCs at a tutorial level. Examples of specific solutions are presented. Advanced concepts are also introduced. Finally, students wishing to pursue this area as a research topic will be exposed to several unsolved issues and hopefully will be inspired to extend the state-of-the-art with new and creative solutions.

    Dr. Aaron Buchwald has 31 years of experience in the field of analog integrated circuit design. He is currently a Fellow at Entropic Communications after their recent acquisition of Mobius Semiconductor, where he was CEO and founder. Prior to founding Mobius Semiconductor, Dr. Buchwald worked at Broadcom, joining as one of the first members of the analog group with the charter to help build a world-class analog team emphasizing design in a mixed-signal environment. Dr. Buchwald's work on embedded CMOS Analog-to-Digital Converters (ADCs) enabled the production of single-chip cable set-top boxes and cable modems with integrated analog front ends and DSP circuitry. His work was awarded the best paper prize in 1997 at ISSCC. Later, Dr. Buchwald was responsible for development of high-speed serial transceivers (XAUI, CX4 and Fiber Channel) at Broadcom. The initial XAUI transceivers were some of the first to employ adaptive receive equalization. Dr. Buchwald was formerly an Assistant Professor at the Hong Kong University of Science and Technology (HKUST). In his early career, Dr. Buchwald spent two years as an analog IC designer at Siemens in Munich Germany. Prior to that, he was with Hughes Aircraft Company in El Segundo, CA. Dr. Aaron Buchwald was born in Ames, Iowa and received a BSEE from the University of Iowa, Iowa City, Iowa, and an M.S. and Ph.D. from the University of California, Los Angeles. He is co-author of the book Integrated Fiber-Optic Receivers. He has taught professional short-courses on data converters and serial transceivers.

    Dr. Mark B. Ketchen

    Thursday, April 10th, 2:00pm-3:00pm
    Room 414, CEPSR

    Microelectronic Test Structures for CMOS Technology

    In scientific investigation and in launching a manufacturing technology through its stages of research and development, test structures are used to facilitate characterization and control of key aspects of the integrated whole. With scaling to deep sub-um dimensions, the cost and complexity of CMOS technologies continues to rise. Appropriately designed test structures add efficiency and reduce cost and time to market. Examples of innovative CMOS test structures and measurement techniques covering from DC to multi-GHz frequencies are described. Emphasis is placed on a methodology that bridges both upward in the hierarchy to complex circuitry and downward to the properties of the constituent components. The designs and concepts presented are based on the work originally done for IBM's microprocessor chip technologies[1].
    [1] Manjul Bhushan and Mark B Ketchen, Microelectronic Test Structures for CMOS Technology,

    Mark B. Ketchen is the sole proprietor of OcteVue, providing technical consulting services in microelectronic technologies. He earned his BS in Physics from MIT in 1970 followed by four years as a Naval Officer and completion of a Ph.D in Physics from UC Berkeley in 1977. He spent 36 years at IBM, holding a variety of positions in science and technology, ranging from individual investigator to serving as Director of IBM's international program in Physical Sciences. He was a pioneer in the design, fabrication and characterization of integrated dc SQUIDs, led design and test efforts in IBM's early attempt to build a superconducting computer, and has recently driven advances in qubits for quantum computing. He worked in silicon bipolar technology integration, ran the silicon fab line at IBM Research in the late 1980s, and worked on design and utilization of custom DC and high speed test structures for CMOS characterization and evaluation at the 180 nm through 32 nm technology nodes. Dr. Ketchen has 43 issued or pending patents over 180 publications and is co-author of the book Microelectronic Test Structures for CMOS Technology published by Springer. He is a Life Fellow of the IEEE, a Life Fellow of the American Physical Society and a past recipient of the American Institute of Physics Prize for Industrial Applications of Physics and the IEEE Leeds award. He is a citizen of the US and Canada and holds a US Government security clearance.

    Dr. Kiran Gunnam
    Violin Memory

    Friday, May 2nd, 2:30pm-4:30pm
    750 Interschool Lab, CEPSR

    VLSI Architectures for Communications and Signal Processing

    Part 1 of this lecture covers introduction to VLSI architectures for Communications and Signal Processing Systems. Various topics include pipelining and parallel processing, retiming, unfolding, folding, systolic architecture design and algorithmic transformations. The emphasis is how to design high-speed, low-area, and low-power VLSI systems for a broad range of DSP and communication applications.
    Part 2 of this lecture covers speaker's research. Low-Density Parity-Check codes now have been firmly established as coding technique for communication and storage channels. This talk gives an overview of the speaker's research and contributions in the development of low complexity iterative LDPC solutions for Turbo Equalization for magnetic recording storage channels. Complexity is reduced by developing new or modified algorithms and new hardware architectures viz. system level hardware architecture, statistical buffer management and queuing, local-global interleaver, LDPC decoder and error floor mitigation schemes.

    Kiran Gunnam received the MSEE and PhD in Computer Engineering from Texas A&M University, College Station, TX. He currently works as Director of Engineering at Violin Memory. He previously held research and development positions at Nvidia, Certicom, LSI, Marvell Semiconductor, Starvision Technologies, Schlumberger, Intel and Texas Engineering Experiment Station. Dr. Gunnam has extensive research and development work experience in complex data path and control path systems. Dr. Gunnam is an expert in IC implementation of communications and signal processing systems. His PhD research contributed several key innovations in advanced error correction systems based on low-density parity- check codes (LDPC) and led to several industry designs. He has done extensive work on ASIC hardware architecture, micro-architecture and digital IC implementation for different systems (IEEE 802.11n Wi-Fi, IEEE 802.16e WiMax, IEEE 802.3 10-GB, Holographic read channel, HDD read channel and Flash read channel). Dr. Gunnam has around 75 patents/patent applications/invention disclosures on hardware architecture and micro-architecture (46 issued patents, 4 pending patent applications and 25 more invention disclosures). He is the lead inventor/sole inventor for 90% of them. He is an IEEE Senior Member. He is also an IEEE Solid State Circuits Society Distinguished Lecturer for 2013 and 2014.

    Spring 2014 Seminars
  • Title : Compact Thermal Sensors in Intel Processors from 90nm to 22nm
    Speaker: Dr. Joseph Shor, Intel Yakum
  • Date: Monday, Deb 17th, 12:00pm-1:00pm, 825 Mudd

  • Title : A simple method to calculate the power spectrum of distorted wide-band signals
    Speaker: Dr. Alessandro Piovaccari, Silicon Labs
  • Date: Friday, March 14th, 2:00pm-3:00pm, 227 Mudd

  • Title : Cognitive Radio Transceiver Chips (SSCS Distinguished Lecture)
    Speaker: Dr. E.A.M.Klumperink, University of Twente
  • Date: Monday, March 31st, 12:00pm-1:00pm, 825 Mudd

  • Title : Challenges of Calibrated Time-Interleaved High-Speed ADCs
    Speaker: Dr. Aaron Buchwald, Entropic Communications
  • Date: Friday, April 4th, 2:00pm-3:00pm, 227 Mudd

  • Title : Microelectronic Test Structures for CMOS Technology
    Speaker: Dr. Mark B. Ketchen, OcteVue
  • Date: Thursday, April 10th, 2:00pm-3:00pm, 414 CEPSR Mudd

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