1. Component arrangement rules
1). Under normal conditions, all components should be arranged on the same surface of the printed circuit. Only when the top layer components are too dense, can some devices with limited height and low heat generation, such as chip resistors, chip Capacitors, pasted ICs, etc. are placed on the bottom layer.
2). On the premise of ensuring the electrical performance, the components should be placed on the grid and arranged parallel to each other or vertically in order to be neat and beautiful. Generally, components are not allowed to overlap; the components should be arranged compactly, and the input and output components should be kept as far away as possible .
3). There may be a high potential difference between certain components or wires, and the distance between them should be increased to avoid accidental short circuits due to discharge and breakdown.
4). Components with high voltage should be arranged in places that are not easily accessible by hand during debugging.
5). Components located on the edge of the board, at least 2 board thicknesses away from the edge of the board
6). Components should be evenly distributed and densely distributed on the entire board.
2. According to the signal direction layout principle
1). Usually arrange the position of each functional circuit unit one by one according to the flow of the signal, centering on the core component of each functional circuit, and layout around it.
2). The layout of the components should be convenient for signal circulation, so that the signals can be kept in the same direction as possible. In most cases, the flow direction of the signal is arranged from left to right or from top to bottom, and the components directly connected to the input and output terminals should be placed close to the input and output connectors or connectors.
3. Prevent electromagnetic interference 1). For components with strong radiated electromagnetic fields and components that are sensitive to electromagnetic induction, the distance between them should be increased or shielded, and the direction of component placement should be in line with the adjacent printed wires cross.
2). Try to avoid mixing high and low voltage devices, and devices with strong and weak signals interlaced together.
3). For components that generate magnetic fields, such as transformers, speakers, inductors, etc., attention should be paid to reducing the cutting of printed wires by magnetic force lines during layout. The magnetic field directions of adjacent components should be perpendicular to each other to reduce the coupling between them.
4). Shield the interference source, and the shielding cover should be well grounded.
5). For circuits operating at high frequencies, the influence of distribution parameters between components should be considered.
4. Suppress thermal interference
1). For heating components, they should be arranged in a position that is conducive to heat dissipation. If necessary, a radiator or a small fan can be installed separately to reduce the temperature and reduce the impact on adjacent components.
2). Some integrated blocks with large power consumption, large or medium power tubes, resistors and other components should be arranged in places where heat dissipation is easy, and they should be separated from other components by a certain distance.
3). The heat-sensitive element should be close to the element under test and kept away from the high-temperature area, so as not to be affected by other heat-generating equivalent elements and cause malfunction.
4). When placing components on both sides, generally no heating components are placed on the bottom layer.
5. Layout of adjustable components
For the layout of adjustable components such as potentiometers, variable capacitors, adjustable inductance coils or micro switches, the structural requirements of the whole machine should be considered. If it is adjusted outside the machine, its position should be adapted to the position of the adjustment knob on the chassis panel; If it is adjusted inside the machine, it should be placed on the printed circuit board where it is adjusted. Design of printed circuit board SMT circuit board is one of the indispensable components in surface mount design. SMT circuit board is a support for circuit components and devices in electronic products, which realizes the electrical connection between circuit components and devices. With the development of electronic technology, the volume of pcb boards is getting smaller and smaller, and the density is getting higher and higher, and the layers of pcb boards are constantly increasing. Higher and higher.
Post time: May-04-2023