First, the power supply plane and ground plane should meet 20h rules
Second, when the power supply layer, the number of underlying and the line layer of the signal is determined, in order to make the relative arrangement of the PCB have a good EMC performance, the relative arrangement positions are basically required:
Under the component layer (second layer) is a ground plane, a device shield layer is provided and a reference plane is provided for the top wiring.
All signal layers are as close as possible to ground planes
Try to avoid the two signal layer traces adjacent. If it is unavoidable, the line spacing of adjacent signal layers should be increased, and the two-layer signal line traces should be vertically routed in the upper and lower positions.
The main power is as close as possible to correspond to it, and minimizes the distance between the power and the plane, it is excellent in less than 5 mil, preferably not more than 10 mils.
The symmetrical stack of laminated structures also takes into account the PCB manufacturing process and controlling the warpage of PCB. Usually civil products use IPC_II standards, requiring PCB's warpage to be less than 0.75%.
Using an even layer structure.
Third, common PCB laminate structure
1, laminated structure of the four-layer board:
TOP, GND02, PWR03, BOTTOM; (there is a complete plane below the TOP layer to optimally arrange the key signal, the key signal should be preferentially arranged in this layer. The distance between the power supply plane and the ground plane should not be too thick, preferably no more than 5 mils.
TOP, PWR02, GND03, BOTTOM; (this scheme and protocol A)
GND01, S02, S03, GND04 / PWR04 (in order to achieve a certain shielding effect, sometimes use this scheme)
2, laminated structure of the six-layer board
TOP, GND02, S03, PWR04, GND05, BOTTOM (this scheme is the laminated design of the 6-layer PCB of the industry, 3 wiring layers, a power plane, 2 ground planes. 4th, 5th floors Thickness should be as best as possible 3 floors, telling the signal and high risk signal priority to this layer)
TOP, GND02, S03, S04, PWR05, BOTTOM (this solution can be employed when the cost requirements are harsh, and S03 is the optimal wiring layer in this scheme)
TOP, S02, GND03, PWR04, S05, BOTTOM (3rd, 4th floors) The thickness of the core plate is minimized, the power supply impedance is low, the first, 2 floors should cross the line, the 5th, 6th floor to cross the line S02 near the ground is the optimal wiring layer)
3, the laminated structure of octave
TOP, GND02, S03, GND04, PWR05, S06, GND07, BOTTOM (laminated scheme for industry, S03 is the optimal wiring layer)
TOP, GND02, S03, PWR1_04, GND05, S06, PWR2_07, BOTTOM (This scheme is used for power type, and a power supply cannot meet the PCB power supply requirements, and the PCB power has intersive; line 3 and 6th floor Is the best wiring layer)
TOP, GND1_02, S03, S04, PWR05, GND2_07, BOTTOM (this laminate power supply plane and ground plane decoupling effect is very poorly applied to more and more cost-controlled design, such as consumer class Plate; Layer 2 and 6th layer are better wiring layers, generally in the flat panel design, DDR and other high-speed signals are arranged in TOP layers after classification of signal properties, and the third layer, 6th, and 8th floors. The laminated design should increase the distance between the 3rd, 4th floors and cross the line)
4, tenth floor laminate structure
TOP, GND1_02, S03, S04, GND2_05, PWR06, S07, S08, GND3_09, BOTTOM (Single power plane scheme priority adopts this stacking scheme)
TOP, GND1_02, S03, S04, PWR1_05, GND2_06, S07, S08, PWR2_09, BOTTOM (3, 7 layers are the best wiring layer)
TOP, GND1_02, S03, GND2_04, PWR1_05, PWR2_06, GND3_07, S08, GND4_09, BOTTOM (this plan is recommended in the case of high cost requirements, EMC requires high and must be recommended in power supply requirements; 3, 8 layers is the most The line layer can be appropriately increased by 5, 6 floors of two power supply planes), read full text, original title: PCB laminate structure of PCB EMC design
Article Source: [Micro Signal: McUgeek, WeChat public number: car CAN bus] Welcome to add attention! Please indicate the source of the article.
Our other product:
