资料介绍
PCB Stack-Up -- Part 2 - Four-Layer Boards
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PCB Stack-Up
Part 2. Four-Layer Boards
The most common four-layer board configuration is shown in Fig. 1 (power
and ground planes may be reversed). It consists of four uniformly spaced
layers with internal power and ground planes. The two external trace layers
usually have orthogonal trace routing directions.
_____________ Sig.
_____________ Ground Figure 1
_____________ Power
_____________ Sig.
Although this configuration is significantly better than a two-layer board,
it has a few, less that ideal characteristics. With respect to the list of
objectives in Part 1, this stack-up only satisfies objective (1). If the
layers are equally spaced, there is a large s