Interconnect and Packaging Lecture 3: Skin Effect

1. Interconnect and PackagingLecture 3: Skin Effect Chung-Kuan Cheng UC San Diego

2. Outlines • Transmission Line Model • Spectrum of Configurations • Skin Effect • Coaxial Cable

3. I. Transmission Line Model • Voltage drops through serial resistance and inductance • Current reduces through shunt capacitance • Resistance increases due to skin effect • Shunt conductance is caused by loss tangent

4. I. Interconnect Model • Telegrapher’s equation: • Propagation Constant: • Wave Propagation: • Characteristic Impedance

5. I. Interconnect Model • Propagation Constant: • Wave Propagation: • Characteristic Impedance

6. I. Interconnect Model (Constants)

7. II. Spectrum of Configurations

8. III. Skin Effect Assuming that resistance and capacitance are negligible. Skin Depth (Equivalent Depth of Uniform Current)

9. III. Skin Effect Boundary condition: • Charges at the boundary shield the electric field. • Thus, capacitance C does not change with frequency.

10. IV. Coaxial Cable

11. IV. Coaxial Cable: Inductance

12. IV. Coaxial Cable: Inductance

13. IV. Coaxial Cable: Inductance

14. IV. Coaxial Cable: Impedance

15. IV. Coaxial Cable: Impedance

16. Skin Effect