When we Reverse Engineering Radio Frequency Circuit Board Layout, there are some rules must be followed:
General principle of Radio Frequency Circuit Board layout: The components should be arranged in the same direction as possible. By selecting the direction of PCB board into the molten tin system, the phenomenon of poor soldering can be reduced or even avoided;
According to experience, there should be at least 0.5mm between devices. The pitch of 5 mm can meet the soldering requirements of components, if PCB board space allows, and the spacing of components should be as wide as possible. For double-sided printed circuit board, one side should be designed with SMD and SMC components, and the other side with discrete components.
Attention should be paid to the PCB card layout replication:
(1) First determine the position of the interface components with other PCB boards or systems on the PCB board. You must pay attention to the coordination problems between the interface components (such as the direction of the components);
(2) Because the size of electronic portable product is very small and the arrangement of the components is very compact, for larger components, the coordination problem must be considered, so priority must be given to determine the corresponding position;
(3) Carefully analyze the circuitry design structure, and perform block processing on the circuit (such as high-frequency amplification circuit, mixing circuit and demodulation circuit, etc.), as far as possible to separate the strong electric signal and the weak electric signal, and the digital signal circuit and the analog signal circuit Separate, circuits that accomplish the same function should be arranged as far as possible.
Within a certain range, to reduce the signal loop area, the filter networks of each part of the circuit must be connected nearby, which can’t only reduce radiation, but also reduce the probability of being interfered, and improve the anti-interference ability of the circuit;
(4) According to the different sensitivity levels of the electromagnetic compatibility of the unit circuit in use, the components that are susceptible to interference in the circuit should also be arranged to avoid interference sources (such as interference from the CPU on the data processing board).
