PCB wiring refers to paving and repairing the path of energized signals to connect various components. In PCB presets, routing is a critical step in completing product presets.

What are some common rules for PCB circuit board wiring?

● 01 Route direction restraint rules

During PCB wiring, the wiring directions of adjacent layers are in an orthogonal structure to prevent different signal lines from running in the same direction on adjacent layers, so as to reduce the indispensable interlayer tampering. When the PCB wiring is inevitably exposed to parallel wiring, the problem should be considered to isolate each wiring layer with the simplest surface, and use the ground wire to isolate each signal line.

● 02 Open-loop detection rules for traces

During PCB wiring, in order to prevent the "receiving antenna effect" arising from the wiring, and to reduce the indispensable interference radiation and capture, it is generally not allowed to expose the wiring method with one end floating.

● 03 Wire length restraint rules

Make the wiring length as short as possible by default to reduce the interference problem caused by the long wiring. For working conditions that drive multiple components, the network topology to be used as deemed appropriate should be voted on based on the specific working conditions.

● 04 Impedance matching detection rules

The wiring width of the same network should be maintained exactly the same. The variation of the line width will cause the special characteristic impedance of the line to be uniform. When the transmission speed is high, reflection will occur in special cases. Under certain conditions, there may be no way to prevent the line width from changing, and efforts should be made to reduce the effective length of the half-middle waist that is not exactly the same.

● 05 Chamfering rules

During PCB wiring, the corners of the traces should be prevented from being preset to acute angles and 90-degree angles, so as to avoid indispensable radiation; it is required that the angle between all wires and wires should be greater than or equal to 135°? In the case of angled corners, two improvement methods can be taken: one is to change the 90° corner into two 45° corners; the other is to use rounded corners as deemed appropriate?

● 06 Component decoupling rules

An indispensable decoupling capacitor is added on the printing plate to filter out the interference signal on the power supply and make the power supply signal stable.

● 07 3W rule

In order to reduce the crosstalk between lines, the line spacing should be large enough. When the line core spacing is not less than 3 times the line width, 70% of the electric field can be maintained without mutual interference, which is called the 3W rule.

● 08 Ground return rules

The minimum loop rule, that is, the size of the ring plane or the surface of the object formed by the signal line and its loop should be as small as possible.

● 09 Shield best care

For signals that are especially critical to one point and have a particularly high frequency, you should think about the problem and think it is appropriate to use the shielding structure of the copper coaxial cable, and isolate the line to be laid with ground wires. It is used to join with the simplest noodle tube in practice.

● Resonance rule for 10 traces

Mainly for high-frequency signal presets, that is, the wiring length cannot be a multiple of its wavelength, so as to avoid resonance.