(1) Components are best placed on one side
If it is necessary to place components on both sides, pin-type components must be placed on the bottom layer, which may cause the circuit board to be difficult to place and not conducive to soldering.
Therefore, it is best to place only SMD components on the bottom layer, which is similar to the layout of components on the common computer graphics card PCB board. When placed on one side, only one side of the circuit board needs to be silk-screened, which is convenient for cost reduction.
(2) Reasonably arrange the position and direction of the interface components
Generally speaking, components connected to power and signal lines are usually placed on the edge of the circuit board, such as serial ports and parallel ports.
If it is placed in the center of the circuit board, it is obviously not conducive to wiring and connector components.
It is also impossible to connect because of the obstruction of other components. In addition, pay attention to the direction of the interface when placing the interface, so that the connecting wire can be drawn out smoothly, away from the circuit board.
After the interface is placed, the type of the interface should be clearly marked with the String (character string) of the interface component.
For the power interface, the voltage level should be marked to prevent the circuit board from being burned due to wrong wiring.
(3) A wide electrical isolation zone is required between high and low voltage components
It is better to have a wide electrical isolation zone between high-voltage components and low-voltage components.
Do not place components with very different voltage levels together, which is not only conducive to electrical insulation, but also has great benefits for signal isolation and anti-interference.
(4) Components with close electrical connections
Components that are closely connected are best placed together.
This is the idea of modular layout.
(5) Noisy components
For example, high-frequency devices such as clock generators and crystal oscillators should be placed at the clock input as much as possible.
High-current circuits and switching circuits are also prone to noise, and these components or modules should also be kept away from high-speed signal circuits such as logic control circuits and storage circuits during layout.
Try to use the control board combined with the power board, and use the interface to connect, so as to improve the overall anti-interference ability and work reliability of the circuit board.
(6) Power supply and chip
Place decoupling capacitors and filter capacitors as much as possible around the power supply and chip.
The arrangement of decoupling capacitors and filter capacitors is an important measure to improve the power quality of the circuit board and improve the anti-interference ability.
In practical applications, the traces, pin connections, and wiring of printed circuit boards may cause large parasitic inductance in practical applications, resulting in high-frequency ripples and glitches in power waveforms and signal waveforms.
However, placing it between the power supply and the ground may bring large parasitic inductance, resulting in high-frequency ripples and glitches in the power supply waveform and signal waveform.
A 0.1F decoupling capacitor can effectively filter out these high-frequency ripples and burrs.
If chip capacitors are used on the circuit board, the chip capacitors should be placed close to the power pins of the components.
For the power conversion chip or the power input terminal, it is best to arrange a 10F or larger capacitor to further improve the power quality.
(7) Number of components
The numbers of components should be arranged close to the frame, uniform in size, neat in direction, and not overlapping with vias and pads.
The first pin of the component or connector indicates the direction.
The signs of positive and negative poles should be clearly marked on the PCB and are not allowed to be covered.
Power Conversion Components：
- DC/DC Converter
- linear conversion power supply
- switching power supply
There should be enough space for heat dissipation and installation, and enough space for welding on the periphery.
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