1.Selection of pcb manufactured components. According to the actual needs of the PCB, conventional components should be selected as much as possible. Do not blindly select too small components or complex IC components, such as 0201 and ultra-fine pitch integrated circuits.
2.Usually the components are arranged on one side of the printed circuit board. This arrangement facilitates soldering, pcb assembly and maintenance. For double-sided pcbs, the main components are assembled on one side of the board, and on the other side are small components, typically surface mount components. Under the premise of ensuring electrical performance requirements, the components shall be parallel or perpendicular to the board surface and main board edge, and the distribution on the board surface evenly and neatly. Generally, the components must not be placed in overlapping manner. If it is necessary to overlap, the structural device should be used for fixing.
3.Components should be arranged as regularly as possible to achieve a uniform assembly density. There should be sufficient distance between the thermal components and other components around the high-power components. The direction and density of the components are arranged to facilitate air convection. Components should be arranged in a straight line in the order of the schematic diagram, and strive to be compact to shorten the length of the printed conductor. If the circuit must be divided into several pieces due to board size limitations or shielding requirements, each printed circuit board should be a separate functional circuit for individual adjustment, testing and maintenance. The circuit board should have the smallest number of leads.
4.In order to minimize the mutual influence and interference of components on the printed circuit board, the components of the high frequency circuit and the low frequency circuit, the high potential and the low potential circuit cannot be too close. The components should be arranged in a direction perpendicular to the adjacent printed conductors. In particular, inductive devices and components with magnetic cores should pay attention to the direction of their magnetic field. The axis of the coil should be perpendicular to the printed circuit board surface to minimize interference with other parts.
5.Consider the heat dissipation and thermal effects of components. Components with large heat should be placed in a position that is facilitated for heat dissipation, such as near the heat dissipation holes. A heat sink should be added if the operating temperature of the component is above 40 °C. When the heat sink is small, it can be directly fixed to the component. When the volume is large, it should be fixed on the bottom board. When designing a printed circuit board, consider the volume of the heat sink and the temperature effect on the surrounding components.
6.Improving the anti-seismic and impact resistance of printed circuit boards. The load on the board should be distributed reasonably to avoid excessive stress. Large and heavy components are placed as close as possible to the fixed end, or add metal structural device to fix. If the printed circuit board is relatively narrow, it may be considered to be reinforced with reinforcing ribs.
7.The layout of components should meet the requirements of reflow soldering and wave soldering. When double-sided reflow welding is adopted, large components should be distributed on one side and small components on the other side, so as to prevent components from falling into the reflow furnace on the first side (small components) that have been welded when reflow welding the second side (large components);When using one-side for reflow welding and one-side for wave soldering, large mounting components should be distributed on the reflow welding surface, while small components should be distributed on the wave welding surface.
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