Multilayer circuit board is recommended in high speed PCB design. Firstly, the inner layer of the multilayer circuit board is specially assigned to the power supply and the ground, so it has the following advantages:
·The power supply is very stable;
·The circuit impedance is greatly reduced;
·The length of wiring is greatly shortened.
In addition, from the perspective of cost, although the cost of multi-layer circuit board is higher than that of single and double-layer circuit board when the same area is compared, the cost difference between multi-layer circuit board and single and double-layer circuit board is not as high as expected if other factors such as miniaturization of circuit board and convenience of reducing noise are taken into account. According to the data we know, when we simply calculate the area cost of the circuit board, the double-layer circuit board is about 460 RMB / m2, and the four layer circuit board is about 800 RMB / m2. That is to say, if we design the same circuit, if the use area of the four layer circuit board can be reduced to 1 / 2 of the double-layer circuit board, then the cost is basically the same as the double-layer circuit board. Although the cost per unit area of circuit boards will be affected by multi-layer production in batches, there is no price difference of 4 times. If there is a price difference of more than 4 times, as long as we can try to reduce the use area of circuit boards and try to reduce it to less than 1 / 4 of that of double-layer boards.