Journal Articles & Conference Papers
People in ELAB are active members of the scientific community regularly publishing articles in reknowned international journals and papers in conferences. Since 2008 ELAB staff has published more than 45 papers in the various research fields the lab is currently involved into.
A list of recent ELAB publications can be found here.
More detailed results can be obtained in the following research digital research databases:
Linear CMOS RF Power Amplifiers for Wireless Applications
Dal Fabbro, Paulo Augusto, Kayal, Maher
ISBN: 978-90-481-9360-8 (Springer) 2010
The RF power amplifier is a key component in a wireless transceiver and is considered by many as the design bottleneck in the transmitting chain. Linear CMOS RF Power Amplifiers for Wireless Applications addresses two fundamental aspects in RF power amplifier design for integration in CMOS technologies at 2.4, 3.7 and 5.2 GHz: efficiency enhancement and frequency agility.
The well-known linearity–efficiency trade-off is circumvented by employing an efficiency-enhancement technique called the dynamic supply RF power amplifier. The design of this system is described with great detail and compared with other efficiency enhancement techniques.
The frequency agility is achieved with a novel impedance matching network based on coupled inductors. The design of a dual-band RF power amplifier is shown, with a careful analysis of the tunable matching network and its interaction with the rest of the circuit.
The considerations and conclusions drawn throughout this book are based on simulation as well as measurement results from the integrated circuit prototypes carefully built and respecting best practices in RF design.
Stuctured Analog CMOS Design
Danica Stefanovic & Maher Kayal
ISBN 978-1-4020-8572-7 (Springer) 2008
Structured Analog CMOS Design describes a structured analog design approach that makes it possible to simplify complex analog design problems and develop a design strategy that can be used for the design of large number of analog cells. It intentionally avoids treating the analog design as a mathematical problem, developing a design procedure based on the understanding of device physics and approximations that give insight into parameter interdependences.
The proposed transistor-level design procedure is based on the EKV modeling approach and relies on the device inversion level as a fundamental design variable. Since all important design parameters can be expressed as continuous functions of the device inversion level, the design optimum as well as the technology limits can be easily found.
The basic design concept consists in analog cell partitioning into the basic analog structures and sizing of these basic analog structures in a predefined procedural design sequence. The procedural design sequence ensures the correct propagation of design specifications, the verification of parameter limits and the local optimization loops. The proposed design procedure is also implemented as a CAD tool that follows this book.
Finally, as a practical example, the design of analog amplifiers in a hybrid multi-bit Delta-Sigma modulator system is described in detail from system level to transistor level.
Methodology for the Digital Calibration of Analog Circuits and Systems
Marc Pastre and Maher Kayal
ISBN 1-4020-4252-3 (Springer) 2006
Methodology for the Digital Calibration of Analog Circuits and Systems shows how to relax the extreme design constraints in analog circuits, allowing the realization of high-precision systems even with low-performance components. A complete methodology is proposed, and three applications are detailed.
To start with, an in-depth analysis of existing compensation techniques for analog circuit imperfections is carried out. The M/2+M sub-binary digital-to-analog converter is thoroughly studied, and the use of this very low-area circuit in conjunction with a successive approximations algorithm for digital compensation is described. A complete methodology based on this compensation circuit and algorithm is then proposed. The detection and correction of analog circuit imperfections is studied, and a simulation tool allowing the transparent simulation of analog circuits with automatic compensation blocks is introduced.
The first application shows how the sub-binary M/2+M structure can be employed as a conventional digital-to-analog converter if two calibration and radix conversion algorithms are implemented.
The second application, a SOI 1T DRAM, is then presented. A digital algorithm chooses a suitable reference value that compensates several circuit imperfections together, from the sense amplifier offset to the dispersion of the memory read currents.
The third application is the calibration of the sensitivity of a current measurement microsystem based on a Hall magnetic field sensor. Using a variant of the chopper modulation, the spinning current technique, combined with a second modulation of a reference signal, the sensitivity of the complete system is continuously measured without interrupting normal operation. A thermal drift lower than 50 ppm/°C is achieved, which is 6 to 10 times less than in state-of-the-art implementations. Furthermore, the calibration technique also compensates drifts due to mechanical stresses and ageing.