As the applications for electronic circuit boards continue to expand, the demand for greater functionality in smaller products continues to increase. Evolutions in component manufacturing techniques and the range of materials used are the most significant advancements that enable these goals to be largely met. However, using these technological advancements requires improving how boards are designed and built. One of the important of these improvements is the implementation of multilayer PCB design guidelines.
PCBs can be classified in many ways. For example, high-speed and power group boards according to usage or application. The most common categorization is based on the PCB stackup, as listed below.
Single-sided PCBs have parts on one side. This surface is the only signal layer in the stackup.
Double-sided PCBs have two signal layers, which contain components: the top and bottom surfaces.
Multilayer PCBs may be single-sided or double-sided. However, these boards typically have internal signal layers as well.
Although the manufacturing process is similar for all board types listed above, there are additional steps for multilayer PCBs. The inclusion of internal layers requires designers to make decisions and specify board parameters, if and where to use via-in-pads, that are otherwise not necessary.
It may not be intuitive; however, using multiple layers in your stackup affects virtually all aspects of the PCB design process. For example, spacing and clearance routing must now consider the angle of signal traces on adjacent (internal) layers. The most important multilayer PCB design guidelines to implement are described below.
