PCBs are made from various components and complex processes. PCBs can be single-layer, double-layer, or multi-layer, and the manufacturing methods differ depending on the layer structure.
This article will provide a detailed introduction to the component names and corresponding uses of PCB circuit boards, as well as the fabrication of single-layer, double-layer, and multi-layer PCB circuit boards and the main functions of various working layers.
First, printed circuit boards mainly consist of pads, vias, mounting holes, wires, components, connectors, filler, and electrical boundaries. The main functions of each component are as follows:
Solder pad: A metal hole used for soldering component leads.
Vias: Metal holes used to connect component pins between different layers.
Mounting holes: used to secure printed circuit boards.
Conductors: Copper films used for electrical networks to connect component pins.
Connectors: Components used for connecting circuit boards.
Filler: Copper plating used in ground networks can effectively reduce impedance.
Electrical boundary: Used to determine the size of the circuit board; all components on the circuit board must not exceed this boundary.
Secondly, the common board layer structures of printed circuit boards include three types: single-layer PCB, double-layer PCB, and multi-layer PCB. A brief description of these three board layer structures is as follows:
(1) Single-layer board: a circuit board with copper plating on only one side and no copper plating on the other side. Components are usually placed on the side without copper plating, while the copper plating side is mainly used for wiring and soldering.
(2) Double-layer board: a circuit board with copper on both sides, usually called the top layer and the bottom layer. The top layer is generally used as the surface for placing components, and the bottom layer is used as the surface for soldering components.
(3) Multilayer board: This is a circuit board containing multiple working layers. In addition to the top and bottom layers, it also contains several intermediate layers. The intermediate layers can usually be used as conductor layers, signal layers, power layers, ground layers, etc. The layers are insulated from each other, and the connection between layers is usually achieved through vias.
Third, printed circuit boards include many types of working layers, such as signal layers, protective layers, silkscreen layers, and internal layers. The functions of each layer are briefly introduced below:
(1) Signal layer: mainly used to place components or wiring. ProtelDXP usually contains 30 middle layers, namely MidLayer1~MidLayer30. The middle layers are used to place signal lines, and the top and bottom layers are used to place components or copper pours.
(2) Protective layer: It is mainly used to ensure that areas on the circuit board that do not need to be tinned are not tinned, thereby ensuring the reliability of the circuit board operation. TopPaste and BottomPaste are the top solder mask layer and the bottom solder mask layer, respectively; TopSolder and BottomSolder are the solder paste protection layer and the bottom solder paste protection layer, respectively.
(3) Silk screen layer: mainly used to print the serial number, production number, company name, etc. of components on the printed circuit board.
(4) Inner layers: mainly used as signal routing layers. ProtelDXP contains 16 inner layers.
(5) Other layers: mainly includes 4 types of layers.
DrillGuide: Primarily used to indicate the location of drill holes on printed circuit boards.
The above is an introduction to the composition and some of the main functions of a PCB. I hope it will be helpful to you.
