PCBA Control Board Design The most basic process of a circuit board can be divided into three major steps: the design of the circuit schematic, the generation of a network table, and the design of a printed circuit board. Whether it is on the board layout or routing, etc. have specific requirements. For example, input and output traces should be avoided as much as possible to avoid interference. Parallel routing of the two signal lines must be separated by grounding, and the wiring of two adjacent layers should be perpendicular to each other as much as possible, and parasitic coupling is easy to occur in parallel. The power supply and ground should be placed as perpendicular to each other on two layers. In terms of line width, a digital circuit PCB can be used as a circuit with a wide ground line, that is, a ground network (the analog circuit cannot be used in this way), and a large area is used for copper plating.
The following article explains the principles and some details of the design of the microcontroller control board.
1. PCBA control board component layout
In terms of component layout, the related components should be placed as close as possible. For example, clock generators, crystal oscillators, and CPU clock inputs are prone to noise, and should be placed close to them when placed. For those devices that are prone to noise, small current circuits, high-current circuit switching circuits, etc., try to keep them away from the logic control circuit and memory circuit (ROM, RAM) of the microcontroller, and if possible, make these circuits into circuits. The board is good for anti-interference and improves the reliability of the circuit operation.
2. PCBA Control Board Decoupling Capacitor
Try to install decoupling capacitors on critical components such as ROM, RAM, etc. In fact, printed circuit board traces, pin connections, and wiring can all have large inductive effects. Large inductors can cause severe switching noise spikes on the Vcc trace. The only way to prevent switching noise spikes on the Vcc trace is to place a 0.1uF electronic decoupling capacitor between VCC and the power ground. If a surface mount component is used on the board, a chip capacitor can be used to directly abut the component and be fixed on the Vcc pin. It is best to use a ceramic capacitor because of its low electrostatic loss (ESL) and high frequency impedance, and the stability of the capacitor temperature and time is also good. Try not to use tantalum capacitors because of its high impedance at high frequencies.