High Frequency Continuous Time Filters in Digital CMOS Processes

1. Front Matter

   Pages i-xxiii

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2. Introduction

   Pages 1-4

3. Mos Capacitors: Modeling & Potential as Integrating Elements in Continuous Time Filters

   Pages 5-32

4. A Review of Integrator Architectures

   Pages 33-69

5. Time Scaling in Electrical Networks

   Pages 71-94

6. Filter Design

   Pages 95-132

7. Filter Testing and Measured Results

   Pages 133-147

8. Applications of Scaling to Other Filter Techniques

   Pages 149-163

9. Tuning in Continuous-time Filters

   Pages 165-190

10. Back Matter

    Pages 191-213

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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.

• CMOS
• Counter
• Potential
• Standard
• analog
• analog circuit design
• circuit
• computer
• digital system
• filter
• modeling
• network
• radio
• tables
• testing

• Texas Instruments, Incorporated, USA

  Shanthi Pavan

• Columbia University, USA

  Yannis Tsividis

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