Digital CMOS Circuit Design

by Silvia Annaratone

Overview

In light of decreasing feature size and greater sophistication of modern processing technology, CMOS has become increasingly attractive, pro- viding low-power (at moderate frequencies), good scalability, and rail-to- rail operation. For many designers, particularly those approaching VLSI from a system viewpoint, previous experience has been mainly with ratioed NMOS design, and so there is a need to buildon this experienceand make a naturaltransition into CMOS design. Indeed, there ismuch that can bebor- rowed from NMOS experience, mainly centered around the techniques for creating N channel pulldown structures. Based on these contributions, CMOS has now grown to the point where there are several circuit styles which have evolved, and these are amply described in this book. Starting at the level ofthe individual MOSFET, basic building blocks are described, as well as the variety of CMOS fabrication processes in contemporary usage. Circuit style issues are then expandedto providethe user with several useful design methodologies, andmuchcareisgiventoelectricalperformancecon- siderations, including characteristics of interconnect, gate delay, and I/O buffering. This understanding is then applied to macro-sized components, including array multipliers, where the reader acquires a unified view of ar- chitectural performance through parallelism, and circuit performance through scrupulousattentionto device sizingandcontrolofparasiticcircuit elements. In addition, layout techniques to avoid latchup, a consideration not previously encountered by NMOS designers, are given careful treatment.

Product Details

ISBN-13:	9781461294092
Publisher:	Springer US
Publication date:	10/01/2011
Series:	The Springer International Series in Engineering and Computer Science , #16
Edition description:	Softcover reprint of the original 1st ed. 1986
Pages:	384
Product dimensions:	6.10(w) x 9.25(h) x 0.03(d)

Table of Contents

1. Introduction.- 1.1. From nMOS to CMOS.- 1.2. CMOS Basic Gates.- 2. MOS Transistor Characteristics.- 2.1. The MOS Transistor.- 2.2. Parasitic Parameters.- 2.3. Small Geometry MOS Transistor.- 2.4. CMOS Transmission Gate.- 2.5. CMOS Inverter.- 2.6. A More Accurate Model for the CMOS Inverter.- 2.7. CMOS Power Dissipation.- 3. Fabrication Processes.- 3.1. The p-well Fabrication Process.- 3.2. The n-well Fabrication Process.- 3.3. LOCMOS Technology.- 3.4. Latchup.- 3.5. The Twin-tub Fabrication Process.- 3.6. The SOS Fabrication Process.- 3.7. Bulk vs. SOI.- 3.8. Design Rules.- 4. Logic Design.- 4.1. Static Logic.- 4.1.1. Complementary Logic.- 4.1.2. nMOS-like Logic.- 4.1.3. Transmission Gate Intensive Logic.- 4.1.4. Cascode Logic.- 4.2. Dynamic Logic.- 4.2.1. Ripple-through Logic.- 4.2.2. P-ELogic.- 4.2.3. Clocked CMOS Logic.- 4.2.4. Domino Logic.- 4.2.5. NORA Logic.- 4.3. Charge Sharing.- 4.4. Bootstrap Logic.- 4.5. Logic Design at the System Level.- 5. Circuit Design.- 5.1. Resistance, Capacitance, and Inductance.- 5.1.1. Interconnect Resistance.- 5.1.2. Interconnect Capacitance.- 5.1.3. Interconnect Inductance.- 5.1.4. Interconnect Discontinuities.- 5.1.5. Coupling Parameters and Interconnect Delay.- 5.1.6. Diffusion Resistance.- 5.1.7. Contact Resistance.- 5.2. Modeling Long Interconnects.- 5.3. The Concept of Equivalent Gate Load.- 5.4. Delay Minimization.- 5.4.1. Inverter Delay and Sizing.- 5.4.2. Inverter Chain Sizing.- 5.4.3. Inverter Chain Sizing with Stray Capacitance.- 5.5. Transistor Sizing in Static Logic.- 5.6. Transistor Sizing in Dynamic Logic.- 6. Design of Basic Circuits.- 6.1. Storage Elements.- 6.2. Full-adder.- 6.3. Programmable Logic Array.- 6.4. Random-access Memory.- 6.4.1. Memory Cell.- 6.4.2. Decoder.- 6.4.3. Sense Amplifier.- 6.5. Parallel Adder.- 6.6. Parallel Multiplier.- 6.6.1. The Design of a Multiplier Based on the Modified Booth Algorithm.- 6.6.2. Basic Building-blocks Inside the Array.- 6.6.3. The Problem of Sign Extension.- 6.6.3.1. The “Sign Propagate” Method.- 6.6.3.2. The “Sign Generate” Method.- 6.6.4. The Implementation of a 24-bit CMOS Booth Multiplier.- 7. Driver and I/O Buffer Design.- 7.1. CMOS Inverter Delay Estimation.- 7.1.1. Fall-time Delay Estimation.- 7.1.1.1. Region 1: n-channel Device in Saturation.- 7.1.1.2. Region 2: n-channel Device in Linear Region.- 7.1.2. Rise-time Delay Estimation.- 7.1.3. Refining the Model.- 7.2. Input Buffer.- 7.3. Output Buffer.- 7.4. Tri-state Output Buffer and I/O Buffer.- 7.5. Output Buffer and Bus Driver Design Optimization.- 7.5.1. Unconstrained Delay Minimization.- 7.5.2. Constrained Delay Minimization.- 7.6. Input Protection.- 7.7. Output Protection.- 7.8. Driving Large On-chip Loads.- Appendix A. Layout.- A. 1. General Considerations on Layout.- A.2. Layout Methodologies for Latchup Avoidance.- A.3. Layout with Structured Methodologies.- A. 4. Power and Ground Routing.- Appendix B. Interconnect Capacitance Computation.- B. 1. Case 1: Coupled Microstrip Structure.- B.2. Case 2: Coupled Stripline Structure.- Appendix C. Figures from Section 5.4.2.- Appendix D. Delay Minimization Based on Eq. (7-3).- Appendix E. Equations Related to Fig. 7-10.- Appendix F. Symbols and Physical Constants.