Table of Contents:

Definition and Overview

1. Introduction

2. Broadside versus Edge-Coupled Differential Pairs

3. Point of Diminishing Returns: Line Width Increases

4. Mechanical Materials Properties

5. Launch Issues

6. System Measurements

7. Conclusion

8. Appendix

Self-Test

Glossary

PDF of this tutorial

Figures 21 and 22

Figure 21. S21 of 0.5-m Single-Ended Lines, 8 mil

Figure 22. FR–4—S21 of 0.5-m Single-Ended Lines

Figures 23-28: Comparison of Eye Patterns for Different Materials (8-mil lines, edge-coupled, 1 m, 1.25 Gbps)

At slower speeds, the virtues of a less lossy material are not fully realized. Measurements are approximate.

Figure 23. Arlon 25N

Figure 24. Rogers 4000 Series

Figure 25. Polyclad LD621

Figure 26. Nelco 6000 Series

Figure 27. Megtron

Figure 28. FR–4

Figures 29-34: Comparison of Eye Patterns for Different Materials (8-mil lines, edge-coupled, 1 m, 2.5 Gbps)

At higher speeds, the need for a less lossy material becomes more apparent. Measurements are approximate.

Figure 29. Arlon 25N

Figure 30. Rogers 4000 Series

Figure 31. Polyclad LD621

Figure 32. Nelco 6000 Series

Figure 33. Megtron

Figure 34. FR–4

Figure 35. Comparison of Conductor and Dielectric Losses