Notes on the layout of PCBA control board components
1. In the PCB design layout of components, the components related to each other should be placed as close as possible. For example, clock generator, crystal oscillator and CPU clock input terminals are prone to noise. When placing, they should be placed close to each other. For the equipment that is easy to produce noise, small current circuit, large current circuit, switching circuit, etc., should be far away from the single-chip logic control circuit and storage circuit (ROM, RAM) as far as possible. If possible, these circuits can be made into circuit board, which is conducive to anti-interference and improve the reliability of the circuit.
Try to install decoupling capacitors beside key components such as ROM and RAM chips. In fact, PCB wiring, pin wiring and wiring may contain large inductive effect. Large inductors may cause severe switching noise spikes in VCC wiring. The only way to prevent switching noise spikes in VCC wiring is to place a 0.1uF electronic decoupling capacitor between VCC and source. If a surface mount component is used on a circuit board, the chip capacitor can be placed directly against the component and connected to the VCC pin. Ceramic tile capacitors are preferred because of their low ESL static loss, high frequency impedance, and good dielectric stability in the temperature and time range. Since tantalum capacitors have high impedance at high frequency, tantalum capacitors should not be used as much as possible.
