Multilayer PCB design method (M)

The above is the general principles of the PCB layout and wiring, but in practice, the layout of the components and wiring is still a very flexible work, the layout and the connections of the components is not the only way, the result of the layout to a large extent depends on the designer's experience and thoughts. In a manner of speaking, there is no a standard to judge the layout and wiring scheme of right and wrong, and can only compare relatively better. So the above layout and wiring principle as a design reference only, the practice is the only standard of judgment.
11.2.3 The special requirements of multilayer PCB layout and wiring
Compared with the simple single plate and double board, multilayer PCB layout and wiring has its unique requirements. For multilayer PCB layout, sum up is to arrange the different power supply and the layout of the types of components. Its purpose is to bring electricity in the back of the segmentation is convenient, but also can effectively improve the anti-interference ability of between components.
The so-called reasonable arrangement of the power supply and to the layout of the type of components, is to use the same power level and the same type of components together as far as possible. For example, when a + on circuit principle diagram, + 5 V, 3.3 V? 5 v, + 15 v,? 15 v, voltage grade, the designer should use the same voltage grade of components placed centrally in the circuit board of a certain area.


Ms Grace Zhang
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Introduction of different layers PCB board

PCB, printed circuit board. As we know, during different function to electronic products, PCB can be divided into different items.Here mainly introduce application of single layer PCB board, double layer PCB board and multilayer board.

Single-Sided PCB board
Single - Sided Boards is the most basic board in PCB field. Components focus on on one side, and wires focused on the other side. Because wires only appear in one side, this kind of PCB is called Single panel (Single sided). Because there are many strict restrictions  to the design of single panel lines(because only one side, every wire can’t the wiring intercross and must follow their own line path), this kind of circuit boards are mostly used in early stage of electronic circuit.

Double-Sided PCB board
Double panel (Double - Sided Boards), wiring exist on both sides of the circuit board, but if want to embody the function of the wiring on both sides, then there must be appropriate circuit connection between two sides. The “bridge” between two sides circuit called guide hole(via). Guide hole is on the PCB layers, these small holes usually filled or coated with metal material, it can be connected to the wires of both sides. Because the volume of double-Sided PCB is double larger than Single-Sided PCB, it solved the difficulty of intercrossing of wires to single layer PCB( circuit can be connected through via to another side), it is more suitable for use in circuit which is more complex than single layer board.

Multilayer boards
Multi - Layer Boards, in order to increase the area where can put wiring, multilayer wiring board using more single or double sided board. Multi-layer PCB is the circuit board which use one sheet of double-sides sheet as inner layer, and two single-sided sheet as outer layer; or use two double-sided sheet as inner layer and two single sided sheet as outer layer, through the positioning system and the alternate insulation bonding materials and conductive graphics interconnection according to design requirement of printed circuit board, then becomes 4 layer and 6 layer printed circuit board, also known as multilayer printed circuit board. Layers of the board does not mean that there are several independent wiring layer, under special circumstances, manufacturer will add empty layer to control board thickness, layer number is usually an even number, and contains the outer two layers. Most of mother board(main board) is four to eight layers board structure, but from technical theory, can be made nearly 100 layers PCB board. Large supercomputers are used with quite layers of motherboard, but because this kind of computer can replaced by many ordinary computer cluster, super multilayer boards are not been used gradually. Because each layer of the PCB are closely combination, generally the actual layer number is not very easy to be seen, but if you look closely at the motherboard, can still see it.