PCB common terms
01
Net ListNet List
A data sheet that represents the connection relationships between component pins on a PCB. It describes all electrical connections on the PCB.
02
Basic Grid
Refers to the vertical and horizontal grid where the conductor layout is positioned when the circuit board is designed. The early grid spacing was 100 mil. Currently, due to the prevalence of fine and dense wires, the basic grid spacing has been reduced to 50 mil.
03
Blind Via Hole
Refers to complex multi-layer boards where some via holes are deliberately not drilled completely because they only need to interconnect certain layers. If one of the holes is connected to the hole ring of the outer layer board, this is cup-shaped. The special hole in the dead end is called a "Blind Hole".
04
Buried Via Hole
Refers to the local via hole of a multi-layer board. When it is buried between the internal layers of the multi-layer board and becomes an "internal via hole" and is not "connected" to the outer layer board, it is called a buried via hole or simply a buried via hole.
05
Through Via
This hole goes through the entire circuit board and can be used for internal interconnections or as mounting locating holes for components. Because through holes are easier to implement in technology and have lower costs, most printed circuit boards use them instead of the other two via holes. Generally speaking, via holes are considered as through holes unless otherwise specified.
06
Fanout fan-out punching
In the PCB layout process, Fanout refers to fan-out drilling. That is, lead short wires from the pad to drill holes, which are divided into two types: automatic and manual.
07
Fine Line
According to the current technical level, four lines between holes or those with an average line width of less than 5 to 6 mil are called thin lines.
08
Current-Carrying Capability
Refers to the maximum current intensity (ampere) that the wires on the board can continuously pass under specified circumstances without causing electrical and mechanical degradation (Degradation) of the circuit board. The ampere of this maximum current is The "current carrying capacity" of the line.
09
Print Package package
The component assembly pattern is made on the printed circuit board according to the actual size (projection) and pin specifications of the components, and consists of multiple pads and surface silk screen printing.
10
Center-to-Center Spacing
Refers to the nominal distance from the center to the center of any two conductors on the board. If conductors are arranged continuously and have the same width and spacing (such as the arrangement of gold fingers), then the "center-to-center spacing" is also called pitch.
11
Conductor Spacing
Refers to the span of a certain conductor on the circuit board surface from its edge to the edge of the other nearest conductor, covering the insulating substrate surface, which is called the conductor spacing, or commonly known as the spacing.
12
Clearance safety distance
The minimum distance to prevent short circuits between signals is an important setting parameter for PCB wiring.
13
Crosshatching
In order to obtain better adhesion to the board surface and green paint in some large-area conductor areas on the circuit board, the copper surface of the sensing part is often turned away, leaving multiple criss-crossing cross lines. Just like the structure of a tennis racket, this will eliminate the risk of floating due to thermal expansion of a large area of copper foil. The etched cross pattern is called Crosshatch, and this improvement is called Crosshatching.
14
Silkscreen Layers
A PCB board can have up to two silk screen layers, namely the top silk screen layer (Top Overlay) and the bottom silk screen layer (Bottom Overlay), which are generally white and are mainly used to place printed information, such as the outline and labeling of components. Comment characters, etc., to facilitate PCB component welding and circuit inspection.
15
Mechanical Layers
It is generally used to place indicative information about board manufacturing and assembly methods, such as PCB outline dimensions, dimension marks, data, via information, assembly instructions and other information. This information varies depending on the requirements of the design house or PCB manufacturer.
16
Ground plane(or Earth Plane) ground plane
It is a type of board that belongs to the inner layer of a multilayer board. Usually, a circuit layer of a multilayer board needs to be matched with a large copper ground layer to serve as grounding, shielding, and heat dissipation for the common circuits of many parts. Heatsinking).