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发表于 2006-8-13 15:32:00
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Contents
* Denotes a section yet to be written or completed.
Process & Methodology 5
Top-Down & Iterative 5
Signal Integrity Engineering Skills 5
Getting Started 6
Reducing Risk & Trusting the Simulation 6
Caveat Emptor 6
The Iterative Process 14
*Robust Design: Plan for DOE of: 15
Introduction 15
Designing the Experiment 15
Set Up and Run the Simulations: 16
Analyze the Results: 16
Optimization and Conclusions: 16
Resources: 17
3Com IBIS Model Standard 18
Variables for Simulation 18
IBIS Variables 18
Symbolic Representation of an IBIS Device – Input Side 20
Symbolic Representation of an IBIS Model – Output Side 21
Composite simulator variables: “Slow-Typ-Fast” 21
SPICE Variables 21
Environmental Variables 21
Board Variables 22
Topology & Termination Variables 24
Receiver Input Impedance and Matching 24
Driver Output Impedance and Matching 24
Performance Factors and Virtual Measurements 26
Switching Delay Times 26
Buffer Delay 26
Propagation Delay 26
First Switch Delay 26
Final Settle Delay 26
Rise Delay/Fall Delay 27
Comments on buffer delay: 27
Crosstalk 27
Ground-Power Bounce/SSN 27
Effect of Reflections on Crosstalk and Ground Bounce 27
Comprehensive Noise Simulation 28
Overshoot/Undershoot 28
Noise Margins 29
Monotonicity Requirements 31
Parasitics 31
Current Requirements/Power Dissipation 31
EMI 32
Signal Integrity 101 33
Tutorial - Courtesy of Cadence Design Systems 33
Signal Integrity Simulation Tools 33
3Com Carrier R&D 3 01/14/03
EMI Control 35
EMI Technical Discussion 35
Introduction 35
Sources and Receivers 35
Noise Signal Paths 36
Near and Far Fields: Coupling Vs Radiation 37
Conducted Paths: 37
Coupled Paths: 38
Radiated Paths: 38
Differential and Common Mode Signals 38
Quieting Source and Receiver: EMI Suppression Components 40
Conduction: Working From the Ground Up: Placement 40
Conduction: Working From the Ground Up: Multi-Point Grounding & Multiple Power Busses 41
Conduction: Working From the Ground Up: Single-Point Grounding 41
Decoupling with Shielding: Layer Stackup 41
Decoupling with Shielding: Fences, Cans, and Guard Traces 42
Decoupling with Distance: Trace Separation 43
Radiation: Faraday Shielding: Fences, Cans, Seams, Etc. 43
Grounding of Shields 43
Radiation: Antennas, Apertures, Seams, Slots, Traces/Corners and Waveguides 44
EMP 44
Absorption, Attenuation and Reflection 44
RF Layout Rules 45
Introduction 45
1. Separate and shield analog and digital signals and ground returns from each other. 45
2. Separate and shield signal grounds and power ground returns from each other. 46
3. Separate and shield input and output stages from each other 46
4. Minimize power line coupling stage-to-stage with bypass capacitors or power line filters or on-board voltage
regulators. 46
5. Treat stage-to-stage coupling capacitors and bypass capacitors as resonant elements, particularly for leaded
components. 47
6. Fan out ground and power traces rather than employing continuous copper if skin effect (ground loop) begins to be
a problem. 47
7. Avoid sharp corners on traces or at trace ends. 48
8. Run controlled impedance, short, match terminated signal traces. 48
9. Replace your discrete circuit with a surface mount ASIC if you don't need the power, voltage standoff, etc. 48
10. Trust nothing to behave ideally. 48
EMI Design Rules 51
Three General Rules: 51
Three Technical Fundamentals: 51
Four Design Techniques: 52
Design Rule Driven EM Control Checking 52
Placement Rules 52
Associated Placement Rules 53
Bypass Rules 53
Power and Ground Plane Rules 54
DC Routing Rules 54
Signal Routing Rules 55
Signal Quality Rules 56
EMI Simulation Tools 56
Interpreting the Results 58
Introduction 58
Waveforms 58
Examples and Value Judgements 58
Lab 1 58
Lab 2 64
Lab 3 67
Lab 4 69
3Com Carrier R&D 4 01/14/03
Waveforms at the Die vs. Waveforms at the Pins 72
Measurement Reports 72
Decisions and Implementing Them: Topology Templates and Constraint Management 73
Death by Analysis 73
Decisions 74
Topology Templates 74
Electrical Constraints 75
Physical Constraints 75
How Simulators Behave 77
Introduction 77
Transmission Lines, Reflection/Bounce Diagrams 77
Newton-Raphson 78
Timing Driven Simulations 78
How to Tell if the Effect of C_comp is being Double-Counted 78
Algorithms Vs. Field Solvers 79
Data Sheets and Verification 79
Relation to High Frequency RF Analysis 82
EMI 82
Data Monotonicity and Convergence 82
Test Measurements and Verification 83
Modeling Oscilloscope Probes for Simulation Results 83
Model Accuracy, Precision and Verification 89
Definitions and Technical Notes 90
Ramp Data: Slew Rate 90
Switching speed: 90
Rise/Fall Definitions: 90
Rise and Fall Times, Slew Rates, V-T Curves and Verification 91
Noise Margin 91
Verifying Your Simulator and IBIS Model 92
Time and Frequency 94
Time, Distance and Frequency: Lumped and Distributed Circuits: Transmission Lines 94
Transmission Line Equations 96
RLGC Matrices 97
Resources & References 97
Web Sites: 98
Signal Integrity Textbooks: 101
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