Operational Amplifiers and Linear Integrated Circuits: Theory and Applications

591 Pages·2018·13.08 MB·English

by  James M. Fiore

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by

James M. Fiore

Version 3.0.9, 01 November 2018
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This Operational Amplifiers & Linear Integrated Circuits: Theory and Application, by James M. Fiore is
copyrighted under the terms of a Creative Commons license:

This work is freely redistributable for non-commercial use, share-alike with attribution
Device datasheets and other product information are copyright by their respective owners

Published by James M. Fiore via dissidents

For more information or feedback, contact:
James Fiore, Professor
Electrical Engineering Technology
Mohawk Valley Community College
1101 Sherman Drive
Utica, NY 13501
www.mvcc.edu/jfiore
[email protected]
Cover photo Canadian Shield by the author
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Welcome to the third edition of this text! The first edition was written circa 1990 and was published by West
Publishing. The title was then purchased by Delmar/Thomson/Cengage some years later and a new edition was
written around 2000 (although it was never tagged as a second edition). That version added a companion
laboratory manual. In the early 2000s the text went from hard cover to soft cover, and in early 2016, Cengage
decided to revert the copyright back to me, the original and singular author. Having already produced a number
of OER (Open Educational Resource) titles including a microcontroller text using the Arduino platform and
numerous laboratory manuals covering DC circuits, AC circuits, Python programming and discrete electronic
devices, it was an obvious decision to go the same route with this book. This third edition includes new specialty
ICs and rewrites of certain sections. If you need information on obsolete legacy ICs such as the NE565,
ICL8038, etc., an OER second edition is available (and for you fans of analog computing, Chapter 10 remains).
The OER lab manual to accompany this text has also been updated to the third edition. It features new exercises
and expansions of the existing ones. If you have any questions regarding the text or lab manual, or are interested
in contributing to the project, do not hesitate to contact me. Finally, please be aware that the most recent
versions of all of my OER texts and manuals may be found at my MVCC web site as well as my mirror site:
www.dissidents.com The original Preface follows, slightly modified.
The goal of this text, as its name implies, is to allow the reader to become proficient in the analysis and design
of circuits utilizing modern linear ICs. It progresses from the fundamental circuit building blocks through to
analog/digital conversion systems. The text is intended for use in a second year Operational Amplifiers course at
the Associate level, or for a junior level course at the Baccalaureate level. In order to make effective use of this
text, students should have already taken a course in basic discrete transistor circuits, and have a solid
background in algebra and trigonometry, along with exposure to phasors. Calculus is used in certain sections of
the text, but for the most part, its use is kept to a minimum. For students without a calculus background, these
sections may be skipped without a loss of continuity. (The sole exception to this being Chapter Ten, Integrators
and Differentiators, which hinges upon knowledge of calculus.)
In writing this text, I have tried to make it ideal for both the teacher and the student. Instead of inundating the
student with page after page of isolated formulas and collections of disjunct facts and figures, this text relies on
building a sound foundation first. While it may take just a little bit longer to “get into” the operational amplifier
than a more traditional approach, the initial outlay of time is rewarded with a deeper understanding and better
retention of the later material. I tried to avoid creating formulas out of thin air, as is often done for the sake of
expediency in technical texts. Instead, I strove to provide sufficient background material and proofs so that the
student is never left wondering where particular formulas came from, or worse, coming to the conclusion that
they are either too difficult to understand completely, or are somehow “magic”.
The text can be broken into two major sections. The first section, comprised of Chapters One through Six, can
be seen as the foundation of the operational amplifier. Here, a methodical, step by step presentation is used to
introduce the basic idealized operational amplifier, and eventually examine its practical limitations with great
detail. These chapters should be presented in order. The remaining six chapters comprise a selection of popular
applications, including voltage regulation, oscillators, and active filters, to name a few. While it is not
imperative that these chapters be presented in the order given (or for that matter, that they all be covered), the
present arrangement will probably result in the most natural progression. Treat these chapters as application
reference material and shape the presentation to your needs.
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There are a few points worth noting about certain chapters. First, Chapter One presents material on decibels,
Bode plots, and the differential amplifier, which is the heart of most operational amplifiers. This chapter may be
skipped if your curriculum covers these topics in a discrete semiconductor or circuit analysis course. In this
case, it is recommended that students scan the chapter in order to familiarize themselves with the nomenclature
used later in the text. As part of the focus on fundamentals, a separate chapter on negative feedback (Chapter
Three) is presented. This chapter examines the four basic negative feedback connections that might be used with
an operational amplifier, and details the action of negative feedback in general. It stresses the popular series-
parallel (VCVS or non-inverting voltage amplifier) form to show how bandwidth, distortion, input impedance,
etc. are affected. Chapter Six presents a variety of modern special purpose devices for specific tasks, such as
high load current, programmable operation, and very high speed. An extensive treatment of active filters is
given in Chapter Eleven. Unlike many texts which use a “memorize this” approach to this topic, Chapter Eleven
strives to explain the underlying operation of the circuits, yet it does so without the more advanced math
requirement of the classical engineering treatment. The final chapter, Chapter Twelve, serves as a bridge
between the analog and digital worlds, covering analog to digital to analog conversion schemes. Please bare in
mind that entire books have been written on the topics of active filters and analog/digital systems. Chapters
Eleven and Twelve are designed as introductions to these topics, not as the final, exhaustive word.
At the beginning of each chapter is a set of chapter objectives. These point out the major items of importance
that will be discussed. Following the chapter objectives is an introduction. The introduction sets the stage for the
upcoming discussion, and puts the chapter into perspective with the text as a whole. At the end of each chapter
is a summary and a set of review questions. The review questions are of a general nature, and are designed to
test for retention of circuit and system concepts. Finally, each chapter has a problem set. For most chapters, the
problems are broken into four categories: analysis problems, design problems, challenge problems, and
computer simulation (SPICE) problems. An important point here was in including problems of both sufficient
variety and number. An optional coverage extended topic may also be found at the end of many chapters. An
extended topic is designed to present extra discussion and detail on a certain portion of a chapter. This allows
you to customize the chapter presentation to a certain degree. Not everyone will want to cover every extended
topic. Even if they aren't used as part of the normal run of the course, they do allow for interesting side reading,
possible outside assignments, and launching points for more involved discussions.
Integrated with the text are examples using popular SPICE-based circuit simulation packages and derivatives
such as the commercial offerings NI Multisim and Orcad PSpice, or free versions such as Texas Instruments'
TINA-TI and LTspice from Linear Technology. If you are not using computer simulations in your courses, these
items may be skipped over with little loss of continuity, however, if you are using simulations, I think that you
will find that this integrated approach can be very worthwhile. Generally, simulations should not be used in
place of a traditional analysis, and with this in mind, many of the examples are used to verify the results of
manual calculations, or to investigate second-order effects which may be too time consuming otherwise.
Computer simulations are also very valuable in the classroom and laboratory as a means of posing “what if”
questions. Some of the items explored include the effects of different op amp models, sensitivity to parameter
sweeps, and the usage of Monte Carlo analysis to investigate typical production spreads. The circuits are
presented using the schematic capture window of Multisim. Although Multisim's schematic editor and output
graphing tools are shown, the figures would be similar in other popular packages. At this level, the differences
between the input and output figures of the various packages are largely cosmetic. In general, any quality
SPICE-based simulator will be sufficient for the circuits presented in this book.
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Finally, there are two elements included in this text which I always longed for when I was a student. First,
besides the traditional circuit examples used to explain circuit operation, a number of schematics of have been
included to show how a given type of circuit might be used in the real world. It is one thing to read how a
precision rectifier works, it is quite another thing to see how one is being used in an audio power amplifier as
part of an overload protection scheme.
The second element deals with the writing style of this text. I have tried to be direct and conversational, without
being overly cute or “chatty”. The body of this text is not written in a passive formal voice. It is not meant to be
impersonal and cold. Instead, it is meant to sound as if someone were explaining the topics to you over your
shoulder. It is intended to draw you into the topic, and to hold your attention. Over the years, I have noticed that
some people feel that in order to be taken seriously, a topic must be addressed in a detached, almost antiseptic
manner. While I will agree that this mindset is crucial in order to perform a good experiment, it does not
translate particularly well to textbooks, especially at the undergraduate level. The result, unfortunately, is a
thorough but thoroughly unreadable book. If teachers find a text to be uninteresting, it shouldn't be surprising if
the students feel the same. I hope that you will find this text to be serious, complete and engaging.
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In a project of this size, there are many people who have done their part to shape the result. Some have done so
directly, others indirectly, and still others without knowing that they did anything at all. First, I'd like to thank
my wife Karen, family and friends for being such “good eggs” about the project, even if it did mean that I
disappeared for hours on end in order to work on it. For their encouragement and assistance, my fellow faculty
members and students. For reverting the copyright back to me so that I could make an OER text, Cengage
Publishing. Finally, I'd like to thank the various IC and equipment manufacturers for providing pertinent data
sheets, schematics, and photographs.
For potential authors, this text was created using several free and open software applications including Open
Office and Dia, along with a few utilities I created myself. The filter graphs found in Chapter Eleven were
created using SciDAVis. Screen imagery was often manipulated though the use of XnView.
I cannot say enough about the emerging Open Educational Resource movement and I encourage budding
authors to consider this route. While there are (generally) no royalties to be found, having complete control over
your own work (versus the “work for hire” classification of typical contracts) is not to be undervalued. Neither
should contributions to the profession or the opportunity to work with colleagues be dismissed. Given the
practical aspects of the society in which we live, I am not suggesting that people “work for free”. Rather,
because part of the mission of institutes of higher learning is to promote and disseminate formalized instruction
and information, it is incumbent on those institutions to support their faculty in said quest, whether that be in the
form of sabbaticals, release time, stipends or the like.
Finally, it is still no lie to say that I couldn't have completed this project without my personal computers; a stack
of Frank Zappa, Kate Bush, King Crimson, Stravinsky and Bartόk CDs; and the endless stream of healthy and
tasty goodies flowing from Karen's kitchen.
- Jim Fiore, February, 2000, ed. 2016
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For Karen

“Information is not knowledge, knowledge is not wisdom.”
-Frank Zappa
“Training is not education.”
- Anon
“My hovercraft is full of eels.”
- Monty Python
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Chapter Objectives . . . . . . . 15
1.1 Introduction . . . . . . . 15
Variable Naming Convention 16
1.2 The Decibel. . . . . . . . 17

Decibel Representation of Power and Voltage Gains 17
Signal Representation in dBW and dBV 23
Items Of Interest In The Laboratory 25
1.3 Bode Plots . . . . . . . . 27
Lead Network Gain Response 28
Lead Network Phase Response 31
Lag Network Response 33
Risetime versus Bandwidth 36
1.4 Combining The Elements - Multi-Stage Effects . . . 38
1.5 Circuit Simulations Using Computers . . . . 40
1.6 The Differential Amplifier . . . . . . 43
DC Analysis 43
Input Offset Current and Voltage 46
AC Analysis 46
Common Mode Rejection 53
Current Mirror 55
Summary . . . . . . . . 58
Review Questions . . . . . . . 58
Problem Set . . . . . . . . 59
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Chapter Objectives . . . . . . . 63
2.1 Introduction . . . . . . . 63
2.2 What Is An Op Amp? . . . . . . 63
Block Diagram Of An Op Amp 64
A Simple Op Amp Simulation Model 69
Op Amp Data Sheet and Interpretation 70
2.3 Simple Op Amp Comparator . . . . . 74
2.4 Op Amp Manufacture . . . . . . 78
Monolithic Construction 78
Hybrid Construction 80
Summary . . . . . . . . 81
Review Questions . . . . . . . 81
Problem Set . . . . . . . . 82
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Chapter Objectives . . . . . . . 85
3.1 Introduction . . . . . . . 85
3.2 What Negative Feedback Is and Why We Use It . . . 85
3.3 Basic Concepts . . . . . . . 86
The Effects of Negative Feedback 87
3.4 The Four Variants of Negative Feedback . . . . 90
Series-Parallel (SP) 91
SP Impedance Effects 98
Distortion Effects 102
Noise 106
Parallel-Series (PS) 106
PS Impedance Effects 109
Parallel-Parallel (PP) and Series-Series (SS) 111
3.5 Limitations On The Use of Negative Feedback . . . 112
Summary . . . . . . . . 113
Review Questions . . . . . . . 113
Problem Set . . . . . . . 114
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Chapter Objectives . . . . . . . 117

4.1 Introduction . . . . . . . 117

4.2 Inverting and Non-inverting Amplifiers . . . . 118

The Non-inverting Voltage Amplifier 118
Inverting Voltage Amplifier 122
Inverting Current-to-Voltage Transducer 126
Non-inverting Voltage-to-Current Transducer 127
Inverting Current Amplifier 130
Summing Amplifiers 133
Non-Inverting Summing Amplifier 136
Differential Amplifier 139
Adder/Subtractor 141
Adjustable Inverter/Non-inverter 142
4.3 Single Supply Biasing . . . . . . 143

4.4 Current Boosting . . . . . . . 146

Summary . . . . . . . . 148

Review Questions . . . . . . . 149

Problem Set . . . . . . . 149

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Chapter Objectives . . . . . . . 156

5.1 Introduction . . . . . . . 156

5.2 Frequency Response . . . . . . 156

5.3 Gain-Bandwidth Product . . . . . . 157

Multi-stage Considerations 163
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