Design Synthesis of Monolithic CMOS Operational Amplifiers


Book Description

This research effort explores efficient methods for the design syn- thesis of monolithic CMOS operational amplifiers. A synthesis system has been developed. It, called OPASYN, takes as inputs system level specifications, fabrication-dependent technology parameters, and geometric layout rules. Based on the general domain of the specifications, the program first selects an appropriate circuit topology from a database using heuristic pruning of the decision tree. Optimal values for the set of design parameters of the chosen circuit are then determined so as to meet the sign objectives. Analytic models of several widely applicable operational amplifier circuit topologies have been developed to eliminate expensive circuit simulation and sensitivity analysis in the inner loop of the optimization step. Subsequently, design- rule-correct mask geometries are constructed using a macro cell layout style. Primitive circuit elements such as transistors, transistor pairs, and capa- citors are produced by parameterized leaf cell generators and assembled accord- ing to circuit-dependent slicing trees that guarantee sound arrangements of the individual components. The synthesis process if fast enough for the program to be interactively used at the system design level by system designers who are inexperienced in op amp design.




Design of CMOS Operational Amplifiers


Book Description

CMOS operational amplifiers (Op Amps) are one of the most important building blocks in many of todays integrated circuits. This cutting-edge volume provides you with an analytical method for designing CMOS Op Amp circuits, placing emphasis on the practical aspects of the design process. This unique book takes an in-depth look at CMOS differential amplifiers, explaining how they are the main part of all Op Amps. The book presents important details and a design method for the different architectures of single ended Op Amps. You find complete chapters dedicated to the critical issues of CMOS output stages, fully differential Op Amps, and CMOS reference generators. This comprehensive book also includes an introduction to CMOS technology and the basics of the physical aspects of MOS transistors, providing you with the foundation needed to fully master the material.




Technology-independent CMOS Op Amp in Minimum Channel Length


Book Description

The performance of analog integrated circuits is dependent on the technology. Digital circuits are scalable in nature, and the same circuit can be scaled from one technology to another with improved performance. But, in analog integrated circuits, the circuit components must be re-designed to maintain the desired performance across different technologies. Moreover, in the case of digital circuits, minimum feature-size (short channel length) devices can be used for better performance, but analog circuits are still being designed using channel lengths larger than the minimum feature sizes. The research in this thesis is aimed at understanding the impact of technology scaling and short channel length devices on the performance of analog integrated circuits. The operational amplifier (op amp) is chosen as an example circuit for investigation. The performance of the conventional op amps are studied across different technologies for short channel lengths, and techniques to develop technology-independent op amp architectures have been proposed. In this research, three op amp architectures have been developed whose performance is relatively independent of the technology and the channel length. They are made scalable, and the same op amp circuits are scaled from a 0.25 um CMOS onto a 0.18 um CMOS technology with the same components. They are designed to achieve large small-signal gain, constant unity gain-bandwidth frequency and constant phase margin. They are also designed with short channel length transistors. Current feedback, gm-boosted, CMOS source followers are also developed, and they are used in the buffered versions of these op amps.




CMOS Current Amplifiers


Book Description

CMOS Current Amplifiers presents design strategies for high performance current amplifiers based on CMOS technology. After an introduction to various architectures of operational amplifiers, the operating principles of the current amplifier are outlined. This book provides the reader with simple and compact design equations for use in a pencil and paper design and the following simulation step. Chapter 1 introduces the general aspects of current amplifiers. After a preliminary classification of operational amplifiers, ideal blocks and models are discussed for different architectures and a first high-level comparison is made between traditional amplifiers and current amplifiers. Analysis and examples of basic circuits, as well as signal processing applications involving current amplifiers, are also given. Non-idealities and second- order effects causing limitations in performance are then discussed and evaluated. Chapter 2 focuses on low-drive current amplifiers. Several design examples for current conveyors and class A current amplifiers are discussed in detail and design equations are presented for the main performance parameters, which allows a good trade-off between requirements. High-performance solutions for high bandwidth and low voltage capability are also considered, and, finally, current comparators with progressively enhanced performance are reported and analyzed critically. Chapter 3 deals with current amplifiers for off-chip loads. Several class AB current-mode output stages are discussed and design strategies which improve performance are presented. A detailed analysis of non-ideal effect is carried out with particular emphasis on linearity. Design examples are given and circuit arrangements for further developments are included. CMOS Current Amplifiers serves as an excellent reference for researchers and professionals of analog IC design, and may also be used as an advanced text on current amplifiers.




Introduction to CMOS OP-AMPs and Comparators


Book Description

A step-by-step guide to the design and analysis of CMOS operational amplifiers and comparators This volume is a comprehensive text that offers a detailed treatment of the analysis and design principles of two of the most important components of analog metal oxide semiconductor (MOS) circuits, namely operational amplifiers (op-amps) and comparators. The book covers the physical operation of these components, their design procedures, and applications to analog MOS circuits-particularly those involving switched-capacitor circuits, and analog-to-digital (A/D) and digital-to-analog (D/A) converters. Roubik Gregorian, a leading authority in the field, gives circuit designers the technical knowledge they need to design high-performance op-amps and comparators suitable for most analog circuit applications. In this self-contained treatment, which is loosely based on his well-received 1986 book, Analog MOS Integrated Circuits for Signal Processing (coauthored with Gabor C. Temes), Gregorian reviews the required basics before advancing to state-of-the-art topics and problem-solving techniques. This valuable guide: * Clearly explains configuration and performance limitation issues affecting the operation of CMOS op-amps and comparators * Details advanced design procedures to improve performance * Provides practical design examples suitable for a broad range of analog circuit applications * Incorporates hundreds of illustrations into the text * Concludes each chapter with problems and references to advanced topics, useful in textbook adoptions Introduction to CMOS Op-Amps and Comparators is invaluable for analog and mixed-signal designers, for senior and graduate students in electrical engineering, and for anyone who would like to keep up with this essential technology.




Low-Voltage CMOS Operational Amplifiers


Book Description

Low-Voltage CMOS Operational Amplifiers: Theory, Design and Implementation discusses both single and two-stage architectures. Opamps with constant-gm input stage are designed and their excellent performance over the rail-to-rail input common mode range is demonstrated. The first set of CMOS constant-gm input stages was introduced by a group from Technische Universiteit, Delft and Universiteit Twente, the Netherlands. These earlier versions of circuits are discussed, along with new circuits developed at the Ohio State University. The design, fabrication (MOSIS Tiny Chips), and characterization of the new circuits are now complete. Basic analog integrated circuit design concepts should be understood in order to fully appreciate the work presented. However, the topics are presented in a logical order and the circuits are explained in great detail, so that Low-Voltage CMOS Operational Amplifiers can be read and enjoyed by those without much experience in analog circuit design. It is an invaluable reference book, and may be used as a text for advanced courses on the subject.




Operational Amplifiers


Book Description

Operational Amplifiers – Theory and Design, Second Edition presents a systematic circuit design of operational amplifiers. Containing state-of-the-art material as well as the essentials, the book is written to appeal to both the circuit designer and the system designer. It is shown that the topology of all operational amplifiers can be divided into nine main overall configurations. These configurations range from one gain stage up to four or more stages. Many famous designs are evaluated in depth. Additional chapters included are on systematic design of μV-offset operational amplifiers and precision instrumentation amplifiers by applying chopping, auto-zeroing, and dynamic element-matching techniques. Also, techniques for frequency compensation of amplifiers with high capacitive loads have been added. Operational Amplifiers – Theory and Design, Second Edition presents high-frequency compensation techniques to HF-stabilize all nine configurations. Special emphasis is placed on low-power low-voltage architectures with rail-to-rail input and output ranges. In addition to presenting characterization of operational amplifiers by macro models and error matrices, together with measurement techniques for their parameters it also develops the design of fully differential operational amplifiers and operational floating amplifiers. Operational Amplifiers – Theory and Design, Second Edition is carefully structured and enriched by numerous figures, problems and simulation exercises and is ideal for the purpose of self-study and self-evaluation.







Compact Low-Voltage and High-Speed CMOS, BiCMOS and Bipolar Operational Amplifiers


Book Description

Compact Low-Voltage and High-Speed CMOS, BiCMOS and Bipolar Operational Amplifiers discusses the design of integrated operational amplifiers that approach the limits of low supply voltage or very high bandwidth. The resulting realizations span the whole field of applications from micro-power CMOS VLSI amplifiers to 1-GHz bipolar amplifiers. The book presents efficient circuit topologies in order to combine high performance with simple solutions. In total twelve amplifier realizations are discussed. Two bipolar amplifiers are discussed, a 1-GHz operational amplifier and an amplifier with a high ratio between the maximum output current and the quiescent current. Five amplifiers have been designed in CMOS technology, extremely compact circuits that can operate on supply voltages down to one gate-source voltage and two saturation voltages which equals about 1.4 V and, ultimate-low-voltage amplifiers that can operate on supply voltages down to one gate-source voltage and one saturation voltage which amounts to about 1.2 V. In BiCMOS technology five amplifiers have been designed. The first two amplifiers are based on a compact topology. Two other amplifiers are designed to operate on low supply voltages down to 1.3 V. The final amplifier has a unity-gain frequency of 200 MHz and can operate down to 2.5 V. Compact Low-Voltage and High-Speed CMOS, BiCMOS and Bipolar Operational Amplifiers is intended for the professional analog designer. Also, it is suitable as a text book for advanced courses in amplifier design.