Signal Integrity: From High-Speed to Radiofrequency Applications

ISBN-13: 9781848215504 / Angielski / Twarda / 2014 / 176 str.

Fabien Ndagijimana

Opis

This book presents the necessary concepts for the design and testing of radiofrequency and high-speed circuits. Signal and propagation theory is presented for the various circuit levels, from the chip to the PCB. The co-existence of high-speed wideband signals of radiofrequency signals and supply circuits is developed in order to provide design rules for engineers and Masters-level students. The subjects covered include: interconnections and signal integrity; spectral analysis techniques for high-speed signals; design techniques for signal integrity; the transmission-line concept; methods for temporal analysis and techniques for frequency domain analysis for connectics.

Signal Integrity discusses the central theories involved in designing and testing radiofrequency and high–speed circuits. It addresses the various circuit levels of signal and propagation theory and the coexistence of high–speed wide band signals, radiofrequency signals, and supply circuits.

Spis treści

INTRODUCTION ix

CHAPTER 1. DEGRADATION OF RISE TIME IN INTERCONNECTS 1

1.1. Propagation issues in interconnects 1

1.1.1. Evolution of digital circuits 1

1.1.2. Evolution of signals in interconnects 2

1.1.3. Propagation time on networks 4

1.1.4. Propagation delay in integrated circuits 5

1.1.5. Spectral analysis of signals 6

1.2. Behavior of components at high frequencies 7

1.2.1. Contact wire behavior 7

1.2.2. Resistance behavior at radiofrequencies (RF) 8

1.2.3. RF inductance behavior 8

1.2.4. Capacitance behavior at RF 9

1.2.5. Effects of losses due to conductors: skin effect 11

1.3. Effect on transmission of signals on interconnects 13

1.3.1. Filtering by transmission channel 13

1.3.2. Degradation of rise time in a limited–bandwidth channel 14

1.3.3. Example of a first–order low–pass RC filter 15

1.3.4. Effects of resistive losses from skin effect 16

1.3.5. Rise time in cascading circuits 17

1.3.6. Transmission quality criteria: eye diagram 19

1.4. Measurement of rise time 19

1.4.1. Different definitions of rise time 19

1.4.2. Measurement principle 20

1.4.3. Effect of measuring sensor 20

1.5. Conclusion 21

CHAPTER 2. ELECTROMAGNETIC MODELING OF INTERCONNECTS 23

2.1. Global modeling of signal integrity 23

2.1.1. ICEM and ICIM models 23

2.1.2. IBIS models 24

2.1.3. I/V characteristics of buffers 25

2.1.4. I/V characteristics of the IBIS model 25

2.2. RC interconnect model 27

2.2.1. RC model 27

2.2.2. The Elmore constant 28

2.3. Capacitive and inductive modeling 28

2.3.1. Capacitive modeling 29

2.3.2. Inductive modeling 30

2.4. LC line modeling 35

2.5. Application to electronic packages and MCM 37

2.5.1. Different types of electronic packages 37

2.5.2. Multichip modules 39

2.5.3. LC modeling of packages 40

2.5.4. 2.5D and 3D electromagnetic simulations 43

2.6. Conclusion 45

CHAPTER 3. CONTROLLED IMPEDANCE INTERCONNECTS 47

3.1. Why control impedance? 47

3.1.1. Effect of interconnect length 47

3.1.2. Classification of interconnects by the signal carried 51

3.2. Influence of rise time on signal degradation 52

3.3. Model of a controlled impedance interconnect 53

3.3.1. Characteristic impedance: definition 53

3.3.2. Configuration of controlled impedance interconnects 54

3.4. Interconnects on PCBs 55

3.4.1. Controlled impedance on PCB 55

3.4.2. Transition between lines and discontinuity 57

3.4.3. Extraction of values from equivalent schema 60

3.5. Impedance control for a microstrip configuration 61

3.5.1. Effect of effective permittivity 61

3.5.2. Limitations on a typical digital circuit 62

3.5.3. Effect of ribbon thickness or protective resin 63

3.6. Analysis of propagation in interconnects 64

3.6.1. Reflection and transmission on termination 64

3.6.2. Reflection and transmission during an impedance break 65

3.6.3. Reflection and transmission on a bus 66

3.7. Effect on data bus configuration 68

3.8. Application to clock distribution 69

3.9. Conclusion 71

CHAPTER 4. PROPAGATION ON TRANSMISSION LINES 73

4.1. Transmission line model 73

4.1.1. Modes of propagation on lines 74

4.2. Propagation modes related to substrate 76

4.2.1. Quasi–TEM mode 77

4.2.2. Skin–effect mode 78

4.2.3. Slow wave mode 79

4.2.4. Transition zone 80

4.3. Equation of propagation on transmission lines 81

4.3.1. Propagation equation 82

4.3.2. Input impedance 85

4.3.3. Interconnect behavior according to length and loads 85

4.3.4. Case of electrically short lines 86

4.4. Conclusion 87

CHAPTER 5. THE S–PARAMETERS TESTING TECHNIQUE 89

5.1. Definition of measured parameters 89

5.1.1. Reflection and transmission 89

5.1.2. Reflection coefficient and SWR on interconnects 90

5.2. The S–parameters principle 92

5.2.1. Definitions 92

5.2.2. Input impedance of a circuit terminated by an impedance 93

5.3. Measurement of S parameters 94

5.3.1. Standard calibrations of a vectorial analyzer 96

5.3.2. Short–open–load–thru (SOLT) calibration 96

5.3.3. Thru–Reflect–Line (TRL) calibration 98

5.3.4. One–port measurement technique 99

5.4. Measurement of characteristic line impedance 100

5.4.1. Short–circuit and open–circuit method 100

5.4.2. R0–loaded line method 102

5.4.3. Equivalent line based on S parameters 103

5.5. Measurement of line capacitance 104

5.5.1. Short–circuit and open–circuit measurement method 104

5.5.2. Loaded line measurement method 104

5.6. Components on PCB and de–embedding techniques 105

5.6.1. Impedance measurement on PCB 106

5.6.2. T and C series matrices 106

5.6.3. ABCD matrix of a transmission line 107

5.6.4. De–embedding procedure 109

5.7. Characterization of dielectric materials for interconnects 111

5.7.1. Metal insulating material metal capacity method for insulating materials in integrated technologies 111

5.7.2. Effective permittivity of a transmission line 113

5.7.3. Case of microribbon, tri–plate or coplanar lines 114

5.8. Conclusion 115

CHAPTER 6. TIME–DOMAIN REFLECTOMETRY ANALYSIS 117

6.1. Principle of TDR 117

6.2. Reflection and transmission of voltage 118

6.2.1. Observable voltages 118

6.2.2. Effects of multiple reflections in high–speed circuits 120

6.3. Measurement of characteristic impedance 120

6.3.1. Impedance measurement with an impulse generator 120

6.3.2. Impedance measurement with an echelon 122

6.3.3. Case of cascaded impedances 123

6.4. Reflection on reactive loads 124

6.5. Extraction of equivalent schemas 125

6.5.1. Definition of equivalent schema 125

6.5.2. Extraction of an inductive discontinuity or component 127

6.5.3. Case of a capacitive discontinuity or component 129

6.5.4. Case of a series inductance and parallel capacitance 131

6.6. Discontinuities in cascade 133

6.6.1. Spatial resolution 133

6.6.2. Example of inductance and capacitance extraction 133

6.7. Conclusion 135

CHAPTER 7. INTERFERENCE AND CROSS–TALK IN INTERCONNECTS 137

7.1. Coupling and interferences due to substrate 137

7.1.1. ICEM model for substrate coupling 138

7.1.2. Guard ring and insulation well 140

7.2. Theory of coupling between lines 140

7.2.1. Interline coupling model 141

7.2.2. Coupling signals at endings 144

7.2.3. Model of coupling in interconnects on PCB 145

7.3. Application to high–speed cables, buses and connectors 150

7.3.1. Stresses in high–speed buses 150

7.3.2. Standardization of data transmission cables 151

7.3.3. Categories of high–speed ethernet systems 153

7.4. Conclusion 155

BIBLIOGRAPHY 157

INDEX 159