Basic Design Process and Layout of PCB Design(2)

3. PCB Layout

(6) Between the power input pin of each integrated circuit and the ground, add a decoupling capacitor (generally a monolithic capacitor with good high-frequency performance is used). When the board space is dense, you can also add a tantalum capacitor around several integrated circuits. .

(7) A discharge diode (1N4148) should be added to the relay coil.

(8) The layout requirements must be balanced, dense and orderly, not top-heavy or heavy-handed. Special attention must be paid to the actual size (occupied area and height) of the components and the distance between the components when placing the components, to ensure the electrical performance of the circuit board and the feasibility and convenience of production and installation. At the same time, under the premise of ensuring that the above principles can be reflected, the placement of the components should be appropriately modified to make them neat and beautiful. For example, the same components should be placed. They should be placed neatly and in the same direction.

This step is related to the overall image of the board and the difficulty of wiring in the next step, so it takes a lot of effort to consider it. When laying out, you can make preliminary wiring and fully consider the places that are not sure about it.

4. Wiring

Wiring is the most important process in the entire PCB design. This will directly affect the performance of the PCB board. In the process of PCB design, there are generally three divisions of wiring. First, the layout is the most basic requirement for PCB design. If the lines are not connected and there are flying lines everywhere, it will be a substandard board. The second is the satisfaction of electrical performance.

This is the standard for measuring whether a printed circuit board is qualified. After the deployment, carefully adjust the wiring to make it achieve the best electrical performance. Then comes appearance. If your wiring is properly routed, there is nothing to affect the performance of the electrical appliance, but it is messy and colorful at first glance. No matter how good your electrical performance is, it is still a piece of rubbish in the eyes of others. This brings great inconvenience to testing and maintenance. The wiring should be neat and uniform, not crisscross and out of order. All of these must be achieved while ensuring the performance of electrical appliances and meeting other individual requirements.