There is an ever increasing trend towards putting entire systems on a single chip. This means that analog circuits will have to coexist on the same substrate along with massive digital systems. Since technologies are optimized with these digital systems in mind, designers will have to make do with standard CMOS processes in the years to come. We address analog filter design from this perspective. Filters form important blocks in applications ranging from computer disc-drive chips to radio transceivers. In this book, we develop the theory and techniques necessary for the implementation of high frequency (hundreds of megahertz) programmable continuous time filters in standard CMOS processes. Since high density poly-poly capacitors are not available in these technologies, alternative capacitor structures have to be found. Met- metal capacitors have low specific capacitance. An alternative is to use the (inherently nonlinear) capacitance formed by MOSFET gates. In Chapter 2, we focus on the use of MOS capacitors as integrating elements. A physics-based model which predicts distortion accurately is presented for a two-terminal MOS structure in accumulation. Distortion in these capacitors as a function of signal swing and bias voltage is computed. Chapter 3 reviews continuous-time filter architectures in the light of bias-dependent integrating capacitors. We also discuss the merits and demerits of various CMOS transconductance elements. The problems encountered in designing high frequency programmable filters are discussed in detail.

Klappentext

There is an ever-increasing trend towards putting entire systems on a single chip. This means that analog circuits will have to coexist on the same substrate along with massive digital systems. Since technologies are optimized with these digital systems in mind, designers will have to make do with standard CMOS processes in the years to come. Filters form important blocks in applications ranging from computer disc-drive chips to radio transceivers. br/ emHigh Frequency Continuous Time Filters in Digital CMOS Processes/em addresses the theoretical and practical problems encountered in the design of robust, programmable continuous-time filters with very high bandwidths, implemented in low-cost digital CMOS technologies. br/ A high performance programmable filter architecture, called `constant-capacitance scaling', is discussed in detail. This technique has the potential for very high-speed operation, and ensures that frequency response shape, noise and dynamic range are maintained as bandwidth is programmed. br/ emHigh Frequency Continuous Time Filters in Digital CMOS Processes/em will be of interest to analog circuit designers as well as researchers interested in filter and network theory.

Inhalt
Mos Capacitors: Modeling & Potential as Integrating Elements in Continuous Time Filters.- A Review of Integrator Architectures.- Time Scaling in Electrical Networks.- Filter Design.- Filter Testing and Measured Results.- Applications of Scaling to Other Filter Techniques.- Tuning in Continuous-time Filters.