Allen and Holberg - CMOS Analog Circuit Design I INTRODUCTION Contents I.1 Introduction I.2 Analog Integrated Circuit Design I.3 Technology Overview I.4 Notation I.5 Analog Circuit Analysis Techniques Page I.0-1 Allen and Holberg - CMOS Analog Circuit Design Organization Chapter 10 D/A and A/D Converters Chapter 11 Analog Systems SYSTEMS Chapter CMOS Comparators Chapter Simple CMOS Opamps Chapter High Performance Opamps COMPLEX CIRCUITS Chapter CMOS Subcircuits Chapter CMOS Amplifiers SIMPLE Chapter CMOS Technology Chapter CMOS Device Modeling DEVICES Introduction Chapter Device Characterization Page I.0-2 Allen and Holberg - CMOS Analog Circuit Design Page I.2-1 I.1 - INTRODUCTION GLOBAL OBJECTIVES • Teach the analysis, modeling, simulation, and design of analog circuits implemented in CMOS technology • Emphasis will be on the design methodology and a hierarchical approach to the subject SPECIFIC OBJECTIVES Present an overall, uniform viewpoint of CMOS analog circuit design Achieve an understanding of analog circuit design • Hand calculations using simple models • Emphasis on insight • Simulation to provide second-order design resolution Present a hierarchical approach • Sub-blocks → Blocks → Circuits → Systems Examples to illustrate the concepts Allen and Holberg - CMOS Analog Circuit Design Page I.2-1 I.2 ANALOG INTEGRATED CIRCUIT DESIGN ANALOG DESIGN TECHNIQUES VERSUS TIME FILTERS AMPLIFICATION Passive RLC circuits Open-loop amplifiers 1935-1950 Active-RC Filters Requires precise definition of time constants (RC products) Feedback Amplifiers Requires precise definition of passive components 1978 Switched Capacitor Filters Requires precise C ratios and clock Switched Capacitor Amplifiers Requires precise C ratios 1983 Continuous Time Filters Time constants are adjustable Continuous Time Amplifiers Component ratios are adjustable 1992 ? Digitally assisted analog circuits ? Allen and Holberg - CMOS Analog Circuit Design Page I.2-2 DISCRETE VS INTEGRATED ANALOG CIRCUIT DESIGN Activity/Item Discrete Integrated Component Accuracy Well known Poor absolute accuracies Breadboarding? Yes No (kit parts) Fabrication Independent Very Dependent Physical PC layout Layout, verification, and Implementation Parasitics extraction Not Important Must be included in the design Simulation Testing CAD Components Model parameters well Model parameters vary known widely Generally complete Must be considered testing is possible before the design Schematic capture, Schematic capture, simulation, PC board simulation, extraction, layout LVS, layout and routing All possible Active devices, capacitors, and resistors Allen and Holberg - CMOS Analog Circuit Design Page I.2-3 THE ANALOG IC DESIGN PROCESS Conception of the idea Definition of the design Comparison with design specifications Implementation Simulation Physical Definition Physical Verification Parasitic Extraction Fabrication Testing and Verification Product Comparison with design specifications Allen and Holberg - CMOS Analog Circuit Design Page I.2-4 COMPARISON OF ANALOG AND DIGITAL CIRCUITS Analog Circuits Digital Circuits are discontinuous in Signals are continuous in amplitude Signal and can be continuous or discrete in amplitude and time - binary signals have two amplitude states time Designed at the circuit level Designed at the systems level Components must have a continuum Component have fixed values of values Customized Standard CAD tools are difficult to apply CAD tools have been extremely successful Requires precision modeling Timing models only Performance optimized Programmable by software Irregular block Regular blocks Difficult to route automatically Easy to route automatically Dynamic range limited by power Dynamic range unlimited supplies and noise (and linearity) Allen and Holberg - CMOS Analog Circuit Design Page I.3-1 I.3 TECHNOLOGY OVERVIEW BANDWIDTHS OF SIGNALS USED IN SIGNAL PROCESSING APPLICATIONS Video Acoustic imaging Seismic Radar Sonar Audio AM-FM radio, TV Telecommunications 10 100 1k 10k 100k 1M 10M 100M Signal Frequency (Hz) Microwave 1G Signal frequency used in signal processing applications 10G 100G Allen and Holberg - CMOS Analog Circuit Design Page I.3-2 BANDWIDTHS THAT CAN BE PROCESSED BY PRESENTDAY TECHNOLOGIES BiCMOS Bipolar analog Bipolar digital logic MOS digital logic MOS analog Optical GaAs 10 100 1k 10k 100k 1M 10M 100M Signal Frequency (Hz) 1G 10G Frequencies that can be processed by present-day technologies 100G Allen and Holberg - CMOS Analog Circuit Design Page I.3-3 CLASSIFICATION OF SILICON TECHNOLOGY Silicon IC Technologies Bipolar Junction Isolated Dielectric Isolated Bipolar/MOS CMOS Aluminum gate MOS PMOS (Aluminum Gate) Silicon gate NMOS Aluminum gate Silicon gate ... CCVS Ai I CCCS Page I. 4-2 Allen and Holberg - CMOS Analog Circuit Design Page I. 4-3 Notation for signals Id id ID iD time Allen and Holberg - CMOS Analog Circuit Design II CMOS TECHNOLOGY Contents... Testing and Verification Product Comparison with design specifications Allen and Holberg - CMOS Analog Circuit Design Page I. 2-4 COMPARISON OF ANALOG AND DIGITAL CIRCUITS Analog Circuits Digital Circuits... areas of the silicon wafer Silicon wafer 0. 5-0 .8 mm 12 5-2 00 mm n-type: 3-5 Ω -cm p-type: 1 4-1 6 Ω -cm Allen and Holberg - CMOS Analog Circuit Design Page II. 1-2 Oxidation The process of growing a layer