Principles of Power Integrity for PDN Design--Simplified: Robust and Cost Effective Design for High Speed Digital Products

Chapter 6. Properties of Planes and Capacitors

6.1 The Key Role of Planes

As a PDN component, the purpose of the power and ground planes in circuit boards or semiconductor packages is to connect the VRM and capacitors to the active devices and deliver a clean power supply to each active device, with an acceptably low voltage noise. The two chief factors that affect the PDN noise in the planes are the transient currents through the active devices and the planes’ impedance.

We refer to the electrical structure created by the adjacent power and ground planes as a cavity. A cavity is any adjacent pair of planes, regardless of their DC voltage. This large, extended structure of conductors with dielectric between them traps any electric and magnetic ...