The basis of SMT processing is PCBs(printed circuit boards), which are distinguished by the number of layers, such as 2-layer PCB and 4-layer PCB. Some supercomputer structures have nearly a hundred layers, however, the most common number of layers in a medical electronics PCBA or automotive electronics PCBA is usually 2 or 4 layers. If you want to know how to choose the number of layers of PCB board reasonably, please read the following introduction about the difference between 2-layer PCB vs 4-layer PCB!
What is 2-layer PCB?
A 2-layer PCB(also called double-layer PCB) is a common type of circuit board that consists of two circuit layers and a dielectric layer. The two circuit layers are connected through some holes to form interconnected and crossed lines and are used to connect other circuit components, devices and equipment.
A 2-layer PCB can usually accommodate more devices and circuits than a single-layer PCB because its two different circuit areas can accommodate more lines and components. With a proper layout and a bare-board manufacturing process, a 2-layer PCB can accommodate a large number of components and connections within the same PCB physical size.
In the manufacturing process of 2-layer PCB, electroless copper and electroplating processes are usually used for printing technology of circuit diagrams and connection surfaces. The manufacturing process is simple and will not cost much, but it is not suitable for complex circuits.
The advantages of a 2-layer PCB are high reliability, flexible wiring, compact structure, mass production and compact circuit board after flip connection can be more easily installed into other equipment. 2-layer PCBs are widely used in consumer electronics, computers, communications, industrial control, and automobiles.
What is 4-layer PCB?
A 4-layer PCB is a common type of printed circuit board, which consists of four circuit layers and three dielectric layers. The 4-layer PCB has two more circuit layers than the 2-layer PCB, providing more signal and power planes, and is more suitable for complex circuits and high-speed signal design.
The 4-layer PCB can adopt different wiring methods, including top surface, bottom surface and inner layer wiring, and has independent power plane and wiring plane. This makes the wiring of the 4-layer PCB more flexible and optimized, allowing for better impedance control and EMC design.
In the manufacture of a 4-layer PCB, the traditional method is to lay two layers of circuit layers and two layers of dielectric layers in the middle on two copper foils respectively, and then compress them together, and drill wiring holes and power lines at the same time.
4-layer PCBs are more technically complex to manufacture than 2-layer PCBs, so they cost more and take longer to design and manufacture. But its advantages are: it has higher signal accuracy and EMC performance, and it is easier to control and prevent electromagnetic interference.
4-layer PCB is usually suitable for electronic products with relatively high signal processing requirements, such as high-end communication equipment, computers, controllers, medical equipment, mechanical equipment control and other fields.
What is the difference between 2-layer PCB vs 4-layer PCB?
A 2-layer PCB and a 4-layer PCB differ in the number of copper layers they have. A 2-layer PCB has two copper layers, one on each side of the board, while a 4-layer PCB has four copper layers, two on each side.
The number of layers in a PCB affects its complexity and functionality. A 2-layer PCB is simpler and more cost-effective for basic designs with fewer components. It is commonly used for simpler electronic devices where space is not a major constraint. On the other hand, a 4-layer PCB offers more flexibility and complexity. It allows for a higher density of components on the board, reducing the size and enhancing the functionality of the device. It also provides better signal integrity and reduces electromagnetic interference.
However, choosing between a 2-layer PCB vs 4-layer PCB depends on the specific requirements of your project, such as the complexity of the circuit, size constraints, and cost considerations.
What’s the use of PCB layers?
In the design, manufacture and application of printed circuit boards (PCB), the number of layers is a very important concept. The number of layers provides different options for the design and implementation of different circuit boards and provides more advantageous solutions for different application scenarios. The following is the role of the number of layers in PCB design:
1. Increase board space: Multilayer PCB can increase the number of components and devices placed in the same physical size, thereby saving space and increasing device density.
2. Reduce circuit noise: More layers also allow signal and power planes to be layered independently, resulting in better anti-interference and control of electromagnetic radiation, reducing circuit noise.
3. Improve signal quality: More layers can realize complex signal transmission, signal processing, power distribution and control circuits, thereby improving signal quality.
4. Improve reliability: In multi-layer printed circuit boards, different layers can be connected through holes and sockets, which reduces the cross-interference between signal and power supply, thereby improving the signal reliability of PCB.
Conclusion
In conclusion, in many applications that require complex board-level layouts, multilayer PCBs have become a mainstream circuit board choice, usually with the advantages of loading more applications per unit area, high speed and high density, anti-interference, and high reliability.
A 2-layer PCB(also called double-layer PCB) is a common type of circuit board that consists of two circuit layers and a dielectric layer. The two circuit layers are connected through some holes to form interconnected and crossed lines and are used to connect other circuit components, devices and equipment.
A 4-layer PCB is a common type of printed circuit board, which consists of four circuit layers and three dielectric layers. The 4-layer PCB has two more circuit layers than the 2-layer PCB, providing more signal and power planes, and is more suitable for complex circuits and high-speed signal design.
A 2-layer PCB and a 4-layer PCB differ in the number of copper layers they have. A 2-layer PCB has two copper layers, one on each side of the board, while a 4-layer PCB has four copper layers, two on each side.
