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PCB Tech

PCB Tech - About multilayer circuit board differences

PCB Tech

PCB Tech - About multilayer circuit board differences

About multilayer circuit board differences

2021-11-07
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Author:Downs

PCB, that is, Printed Circuit Board, is not only the support of electronic components, but also the carrier of electrical connection of electronic components. Before the advent of PCB circuit board, the connection between electronic components was done by direct connection of wires; but now, the wire connection method is only used in laboratory tests, and PCB has occupied an absolute control position in the electronics industry.


The past and present of PCB

The development history of PCB can be traced back to the early 20th century. In 1936, the Austrian Paul Eisler (Paul Eisler) applied PCB in the radio, putting PCB into practical use for the first time; in 1943, the United States widely used the technology in military radios; in 1948, the United States officially recognized that the invention can be used business use. As a result, PCB began to be widely used since the mid-1950s, and then entered a period of rapid development.


Explore the mystery of multilayer circuit board

As PCBs become more and more complex, when designers use development tools to design PCBs, it is easy to confuse the definition and purpose of each layer. When our hardware developers draw the PCB by themselves, it is easy to cause unnecessary misunderstandings in production because they are not familiar with the purpose of each layer of the PCB. In order to avoid this situation, take AltiumDesignerSummer09 as an example to classify and introduce each PCB layer.

Printed Circuit Board

Differences between PCB layers(Signal Layer (SignalLayers)

AltiumDesigner can provide up to 32 signal layers, including the top layer (TopLayer), the bottom layer (BottomLayer) and the middle layer (Mid-Layer). The layers can be interconnected through vias (Via), blind vias (BlindVia) and buried vias (BuriedVia).


Explore the mystery of multilayer circuit boards

1. The top signal layer (TopLayer)

Also called the component layer, it is mainly used to place components. For double-layer boards and multilayer boards, it can be used to arrange wires or copper.

2. BottomLayer

Also called soldering layer, it is mainly used for PCB wiring and soldering. It can be used to place components for double-layer boards and multilayer boards.

3.Mid-Layers

There can be up to 30 layers, which are used to arrange signal lines in a multilayer board. Power lines and ground lines are not included here.

Internal power plane (InternalPlanes)

Usually referred to as the inner electric layer for short, it only appears in multi-layer boards. The number of PCB board layers generally refers to the sum of the signal layer and the inner electric layer. Same as the signal layer, the inner electric layer and the inner electric layer, and the inner electric layer and the signal layer can be connected to each other through through holes, blind holes and buried holes.


Explore the mystery of multilayer circuit boards

SilkscreenLayers

A PCB board can have up to 2 silk screen layers, namely the top silk screen layer (TopOverlay) and the bottom silk screen layer (BottomOverlay), generally white, mainly used to place printed information, such as component outlines and annotations, various notes Characters, etc., to facilitate the soldering of PCB components and circuit inspection.

1. Top screen printing layer (TopOverlay)

It is used to mark the projection outline of the components, the label, the nominal value or the model of the component, and various annotation characters.

2. Bottom Overlay

Same as the top silk screen layer, if all the marks on the top silk screen layer are included, the bottom silk screen layer can be closed.

Mechanical Layers (MechanicalLayers)

The mechanical layer is generally used to place indicative information about board manufacturing and assembly methods, such as the outline dimensions of the PCB, size markings, data materials, via information, assembly instructions and other information. This information varies according to the requirements of the design company or PCB manufacturer. The following examples illustrate our common methods.

1: Generally used to draw the frame of the PCB as its mechanical shape, so it is also called the shape layer;

2: We are used to place the PCBprocessing process requirement form, including information such as size, plate, layer and so on;

The body size information of most components in the ETM library, including the three-dimensional model of the component; for the sake of simplicity of the page, this layer is not displayed by default;

The footprint information of most components in the ETM library can be used to estimate the PCB size in the early stages of the project; for the simplicity of the page, this layer is not displayed by default, and the color is black.

Masking layer (MaskLayers)

AltiumDesigner provides two types of mask layers (SolderMask) and solder paste layer (PasteMask), in which there are two layers, the top layer and the bottom layer, respectively.