PCB Technical - What are the common layout principles for PCB boards?

PCB factories generally have the following layout principles in circuit board production:

1. According to the principle of signal layout

1) The position of each functional circuit unit is usually arranged one by one according to the signal flow, and the core components of each functional circuit are centered and laid out around it.

2)The layout of the components should facilitate the flow of signals, so that the signals are kept in the same direction as possible. In most cases, the signal flow is arranged from left to right or 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.

2. Component arrangement rules

1)Under normal conditions, all components should be arranged on the same side of the printed circuit. Only when the top components are too dense, can some devices with limited height and low heat generation, such as chip resistors and chip capacitors, be installed., IC, etc. are placed on the bottom layer.

2) Under the premise of ensuring electrical performance, the components should be placed on the grid and arranged in parallel or perpendicular to each other to be neat and beautiful. In general, they are not allowed to overlap; the arrangement of components should be compact, and the input and output components should be as far away as possible.

3) The components with high voltage should be arranged as far as possible in places that are not easily reachable by hands during debugging.

4) Components located at the edge of the board should be at least 2 board thickness away from the edge of the board.

5)There may be a relatively high potential difference between certain components or wires, and their distance should be increased to avoid accidental short circuits due to discharge and breakdown.

6)The components should be evenly distributed and densely distributed on the entire board surface.

Multilayer circuit board manufacturers

3. the 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.

4. prevent electromagnetic interference

1)For components with strong radiated electromagnetic fields and components sensitive to electromagnetic induction, the distance between them should be increased or shielded, and the direction of component placement should cross the adjacent printed wires.

2)Try to avoid mixing high and low voltage devices, and interleaving devices with strong and weak signals.

3) For components that generate magnetic fields, such as transformers, speakers, inductors, etc., pay attention to reducing the cutting of the printed wires by the magnetic lines of force during the layout. The magnetic field directions of adjacent components should be perpendicular to each other to reduce the coupling between each other.

4)Shield the interference source, and the shielding cover should have a good grounding.

5) For circuits operating at high frequencies, the influence of the distribution parameters between components should be considered.

5. Suppress thermal interference

1)For heating elements, it should be arranged in a position that is conducive to heat dissipation. If necessary, a radiator or small fan can be installed separately to reduce the temperature and reduce the impact on adjacent elements.

2)Some components with high power consumption, such as integrated blocks, large or high-speed tubes, resistors, etc., should be placed in a place where heat is easy to dissipate, and separated from other components by a certain distance.

3)The thermal element should be close to the component under test and away from the high temperature area, so as not to be affected by other heating power equivalent components and cause malfunction.

4)When components are placed on both sides, heating components are generally not placed on the bottom layer.

In summary, the above are common layout principles for PCB board design