PCB design seems to be complicated. It is necessary to consider the direction of various signals as well as the transmission of energy, and the troubles brought by interference and heating always follow the shape. But in fact, the summary is very clear, can be started from two aspects: to put it bluntly: "how to place" and "how to connect".
1. In accordance with the layout principle of "first big and then small, first difficult and then easy", that is, important unit circuits and core components should be prioritized. This is the same as eating buffet: buffet appetite is limited first pick favorite food, PCB space is limited first pick important pendulum.
2. The main components should be arranged according to the principle block diagram and the main signal flow pattern of the board. The layout should meet the following requirements as far as possible: the overall connection should be as short as possible, and the key signal line should be the shortest; The layout of the decoupling capacitor should be as close to the IC power pin as possible, and make it form the shortest circuit between the power supply and the ground; Reduce the misdirection of signal running and prevent accidents on the road.
3. The arrangement of components should be convenient for debugging and maintenance, that is, large components can not be placed around small components, and there should be enough space around the components to be debugged. If the situation is too crowded, it will often become very awkward.
4, the same structure of the circuit, as far as possible to use "symmetrical" standard layout; Optimize the layout according to the standards of uniform distribution, balanced center of gravity and beautiful layout. Bioneng belongs to Qinji Group, is the leading electronic industry service platform in China, providing online components, sensor procurement, PCB customization, BOM, material selection and other electronic industry supply chain solutions, one-stop to meet the comprehensive needs of small and medium-sized customers in the electronics industry.
5. The plug-in components of the same type shall be placed in the same direction in the X or Y direction. The same type of polar discrete components should also strive to maintain consistency in the X or Y direction, so as to facilitate production and inspection.
6, heating components should generally be evenly distributed, in order to facilitate the heat dissipation of the veneer and the whole machine, in addition to the temperature detection components of temperature sensitive components should be far away from the heat of the components.
7, high voltage, large current signal and small current, low voltage weak signal completely separate; Analog signals are separated from digital signals; High frequency signals are separated from low frequency signals; The spacing of high-frequency components should be sufficient. In component layout, proper consideration should be given to placing the components using the same power supply together as far as possible, so as to facilitate future power separation.
These are the "how to place" or layout of the main considerations. And the "how to connect" is relatively more complicated, in general is:
Key signal line priority: analog small signal, high-speed signal, clock signal and synchronization signal and other key signals priority wiring;
Density first principle: Start wiring from the most complex connections on the board. Start wiring from the most densely wired area of the board.