Pcb Stack-up Analysis And Design, Part 1

摘要

The term "STACK-UP" refers to the arrangement and the types of layers in a multilayer board. The design of a PCB stack-up involves ascertaining the number of signal layers needed to route the board and the ground/power planes demanded for adequate power distribution. It is recommended that the layers are arranged so that each high-speed trace is referenced to a continuous plane. Furthermore, it is desirable for the stack-up to include paral-rnlel (adjacent) power and ground layers for enhancing capaci-tive decoupling and reducing EMI, and the PCB stack-up will strongly influence impedance of a power distribution system (PDS).rnPrepreg (also called B-stage) consists of a glass cloth coated with resin (epoxy) that has not been fully cured. A prepreg layer is applied between two internal layers (or cores) of a multilayer PCB to function as glue through the lamination process. A core is a thin piece of dielectric (cured fiberglass-epoxy resin) with copper foil bonded on both sides. The term laminate also refers, to a composition of two sheets of copper foil laminated to a piece of woven glass cloth saturated with resin and fully cured.