Five requirements for the reasonable layout of various components in PCB circuit board design

Reasonable component layout is the basic prerequisite for designing high-quality PCB circuit board diagrams. The requirements for component layout mainly include five aspects: installation, force application, heat exposure, signal, and aesthetics.

1. Installation

   It refers to a series of basic requirements put forward in specific application scenarios to smoothly install circuit boards into chassis, casings, slots, avoid spatial interference, short circuits and other accidents, and ensure that the designated connectors are in the designated positions on the chassis or casing.

2. Force application

   The circuit board should be capable of withstanding all kinds of external forces and vibrations during installation and operation. For this reason, the circuit board should have a reasonable shape, and the positions of various holes (screw holes, special-shaped holes) on the board should be arranged reasonably. Generally, the distance between the hole and the edge of the plate should be at least greater than the diameter of the hole.

   At the same time, it should be noted that the weakest section of the plate caused by the irregular holes should also have sufficient bending strength. The connectors that directly "extend" out of the equipment casing on the board should be fixed reasonably in particular to ensure the reliability of long-term use.

3. Heating

   For high-power and heat-generating components, in addition to ensuring heat dissipation conditions, it is also necessary to pay attention to placing them in appropriate positions. Especially in precise analog systems, special attention should be paid to the adverse effects of the temperature fields generated by these devices on the fragile preamplifier circuits. Generally, the parts with very high power should be made into a separate module and certain thermal isolation measures should be taken between it and the signal processing circuit.

4. Signal

   Signal interference is the most important factor to be considered in PCB layout design. Several of the most fundamental aspects are: separating or even isolating weak signal circuits from strong signal circuits; The AC part is separated from the DC part. The high-frequency part is separated from the low-frequency part. Pay attention to the direction of the signal line; The layout of the ground wire; Appropriate shielding, filtering and other measures.

5. Aesthetic Appeal

   Not only should the neat and orderly placement of components be taken into account, but also the smooth and elegant wiring. Since laypeople sometimes emphasize the former more to make a one-sided evaluation of the merits and demerits of circuit design, for the sake of the product's image, the former should be given priority when the performance requirements are not strict.

   However, in high-performance scenarios, if double-sided boards have to be used and the circuit boards are also encapsulated inside and not visible in daily use, the aesthetic appeal of the traces should be given priority.

Based on the above five points, I believe many friends are already clear about what to pay attention to when placing the original documents.