0_Index 2014

PRINCIPLES OF ELECTRONICS FOR

MEDICAL PHYSICISTS MDPH611

Pierre Léger Eng. Department of Medical Physics McGill University Health Centre Montreal, Canada September 2014

Printing history: 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014,

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CONDENSED TABLE OF CONTENTS PREFACE ix ACKNOLEDGEMENTS

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PART I BASIC DEVICES AND ANALOG CIRCUITS 1 2 3 4

Semiconductors theory and diodes 1 Bipolar Junction Transistor 29 Field Effect Transistors 67 Operational Amplifiers 93

PART II DIGITAL CIRCUITS 5 6 7

Logic 141 Binary Systems Data converters

APPENDIXES 1 2 3 4 5 6 7 8 9 10

1

174 187

207

Internal source resistance 208 Passive elements 209 Bipolar power supply 218 Superposition theorem 222 Capacitance 228 Inductance 234 Resonant circuit 238 Power transfer 243 Euler formula 246 Sine wave voltage measurement

REFERENCES

140

247

249

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DETAILED TABLE OF CONTENTS PREFACE ix ACKNOLEDGEMENTS

PART I

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BASIC DEVICES AND ANALOG CIRCUITS

1 Semiconductor theory and diodes 1.1 Semiconductor elements 1.1A 1.1B

2

3

Doping elements 3 Electronic diode structure

5

1.2 The diode 6 1.2A 1.2B 1.2C 1.2D

I-V characteristics 7 Thermal characteristics Ideal diode 9 Piecewise linear model

8 9

1.3 Diode types 10 1.3A 1.3B 1.3C 1.3D 1.3E 1.3F 1.3G

Zener diode 10 Light emitting diodes Photodiode 12 Optocouplers 13 Laser diode 14 PIN diode 15 Schottky diode 16

1.4 Diode applications 1.4A 1.4B 1.4C 1.4D

Problems

17

Single phase rectifier bridge (Greatz bridge) Three phase rectifier bridge 19 Voltage multiplier 20 Final note on diodes 22

2.1 The BJT structure

Problems

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29

30

Configuration and operation 31 Transfer Characteristics 35 DC load line 37 DC circuit approximation 40 AC circuit approximation 41 Base-emitter resistance approximation Trans-conductance 44 Breakdown voltage limits 45

2.2 BJT applications 2.2A 2.2B 2.2C 2.2D 2.2E

17

23

2 Bipolar Junction Transistor 2.1A 2.1B 2.1C 2.1D 2.1E 2.1F 2.1G 2.1H

12

42

46

Constant current sources 46 Darlington transistor 47 Silicone controlled rectifier (SCR) 48 Logic switch 49 X-ray tube filament emission control circuit

51

50

1

3

Field Effect Transistors

55

3.1 Introduction 56 3.2 Junction field effect transistor (JFET) 3.3 JFET polarization 60 3.3A 3.3B 3.3C

Gate bias method 61 Self bias method 62 Divider bias method 63

3.4 MOSFET’s 3.4A 3.4B

3.5 CMOS 3.5A 3.5B

65

EMOSFET DMOSFET

66 70

71 CMOS transmission gate or bilateral switch CMOS logic inverter 73

3.6 MESFET 74 3.7 Transistor comparison table Problems 76

4

Operational Amplifiers

75

82

Differential amplifier 83 Offset nulling 84 Buffer amplifier 86 Power amplifier 86

4.3 Modes of operation 4.3A 4.3B 4.3C

86

Single ended mode 86 Differential mode 87 Common mode 87

4.4 Op-amp ideal characteristics

87

4.4A 4.4B

Input impedance 88 Output impedance 88

4.4C

Differential voltage gain:

4.4D

Common mode voltage gain:

4.4E 4.4F

Bandwidth 89 Slew rate 91

4.5 Non-ideal characteristics 4.5A 4.5B

AVd

88 88

AVc

92

Error due to non-infinite input resistance 92 Error due to non-zero output resistance 93

4.6 Op Amp as a linear active device and CMRR 4.7 Non-inverting amplifier 95 4.7A 4.7B 4.7C

72

81

4.1 Introduction 82 4.2 Op-amp internal structure 4.2A 4.2B 4.2C 4.2D

56

Voltage follower (unity gain) A = 1 Non-inverting amp with gain A > 1 Non-inverting amp with gain A < 1

4.8 Inverting amplifier 98 4.9 Single difference amplifier

94 95 96 97

98

4.9A

Gain balancing considerations

4.9B

Difference amplifier voltage gain:

4.9C

Difference amplifier common mode voltage gain:

4.9D

Difference amplifier input resistance:

4.9E

Instrumentation amplifier

4.10 Summing inverter amplifier

99

AVd 100 Rin

AVc 101

103

103

106

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4.11 Integrator

107

4.11A Integrator with ramp control

108

4.12 Differentiator 109 4.13 Comparator 111 4.13A Non-inverting comparator 111 4.13B Inverting comparator 112

4.14 Op-amp application 4.15 Active filters 115 4.15A 4.15B 4.15C 4.15D

Problems

PART II 5

Logic 5.1 5.2 5.3 5.4 5.5 5.6

113

Low pass filter High pass filter Band pass filter Band stop filter

118 120 122 123

124

DIGITAL CIRCUITS

129

130 Introduction 131 Logic families 131 Symbols related to logic states 133 Activity level symbols 134 Logic level and signal information 134 Logic gates 136 5.6A 5.6B 5.6C 5.6D 5.6E 5.6F

5.7 Buffers 5.7A 5.7B 5.7C 5.7D 5.7E 5.7F 5.7G

5.8 Counters 5.9 Flip flops 5.9A 5.9B 5.9 C

5.10 Timers

AND 136 NAND 136 OR 138 NOR 138 XOR 138 XNOR 139

139 Inverter buffer 139 Positive gate enable three state buffer 139 Negative gate enable three state buffer 140 Three state buffer circuit 140 Three state buffer in high impedance mode Z 142 Three state buffer in low output mode L 143 Three state buffer in high output mode H 144

145 147 SR D JK

147 148 149

150

5.10A 74121 timer 150 5.10B 555 timer 151 5.10B1 555 in astable mode 151 5.10B2 555 in monostable mode 154

5.11 Multiplexers 5.11A 5.11B

Problems

vi

154

Digital multiplexer 154 Analog multiplexer 155

156

6

Binary Systems 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8

7

161

Introduction 162 Base 2 system 162 Binary code generation 163 Binary operations 165 Decimal to binary conversion 168 Hexadecimal system 169 Decimal to hexadecimal conversion 171 Grey code generation 171 Problems 172

Data converters

175

7.1 Introduction 176 7.2 Digital to analog converter 7.2A 7.2B

R2R ladder circuit Multiplying DAC

7.3 Analog to digital converters 7.3A 7.3B 7.3C 7.3D 7.3E 7.3F

7.6B

7.6C

7.6D

Problems

184

188

192 193

Resolution 193 Absolute accuracy 193 Relative accuracy 194 Linearity 194 Conversion time 194 Slew rate and settling time

7.6 Data converter errors 7.6A

179 183

Ramping 184 Tracking servo 186 Dual slope 186 Successive approximation register Parallel or flash 189 Half-flash 191

7.4 Sample track hold amplifiers 7.5 Data converter specifications 7.5A 7.5B 7.5C 7.5D 7.5E 7.5F

176

195

195

Fabrication process errors 195 7.6A1 Non-linearity 196 7.6A2 Non-monotonicity 196 7.6A3 Missing codes 197 7.6A4 Differential linearity 197 7.6A5 Offset error 198 7.6A6 Gain error 198 7.6A7 Glitches 199 Temperature and supply errors 200 7.6B1 Drift error 200 7.6B2 Long term drift 200 7.6B3 Supply sensitivity 201 Time errors 201 7.6C1 Aperture error 201 7.6C2 Aperture error minimization Quantizing error 202

202

203

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APPENDIXES 1 2 3 4 5 6 7 8 9 10

REFERENCES

viii

207

Internal source resistance 208 Passive elements 209 Bipolar power supply 218 Superposition theorem 222 Capacitance 228 Inductance 234 Resonant circuit 238 Power transfer 243 Euler formula 246 Sine wave voltage measurement

249

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PREFACE Just few years ago senior physicists expressed a need for a comprehensive approach to electronic basic theory. This new perspective involved a complete redesign of the course given at that time and efforts were made to reach that goal. Therefore finding an appropriate topic selection forming a balanced synthesis between theory and practice became a twofold project mainly dedicated to medical physics students at master’s level. This book contains the following topics. -

Chapter 1 reviews the physics of semiconductor materials and diodes.

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Chapter 2 is dedicated to bipolar junction transistors.

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Chapter 3 covers field effect transistors up to the MESFETs.

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Chapter 4 deals with operational amplifiers and their applications.

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Chapter 5 covers logic components such as gates, counters, flip-flops multiplexers and timers.

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Chapter 6 reviews binary and hexadecimal systems.

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Chapter 7 covers digital to analog converters DAC’s and analog to digital converters ADC’s.

Since quantum theory led to the discovery of the bipolar transistor, nothing has changed regarding their basic properties. But after more than half a century of improvements new versions have emerged like FET, MOSFET and others as well. Therefore the field of transistor application grew almost exponentially. The early 5 mm size transistor has ended the use of heavy radio vacuum tubes. The modern fabrication processes shrunk the transistor down to microscopic scale. The hardware industry built its success on that very basic component by packing millions of them in small plastic packages, called integrated circuits. They run the most powerful computers, high-speed Internet networks and satellite communications as well. This book is dedicated to those in need to review the fundamentals electronic principles of and their use.

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ACKNOWLEDGEMENTS Personally encouraged to do this work by Dr. Ervin Podgorsak, as the Director of the Medical Physics Unit of the McGill University Health Center he provided me tools to put together this material. I must also thank him for his precious tips and advice regarding the presentation of the material. Writing such a document took time and efforts in reaching its first publication in 2005. Since then this document went through a series of revisions and updates. Thanks to many students for their suggestions and help from many colleagues. I would also like to thank our Medical Physics secretary Ms. Margery Knewstubb, for her kind help in revising my text and her recommendations on many occasions.

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