How to connect the various components in the PCB design from szcaravan's blog

Table of content：

1. No cross circuit is allowed in the printed circuit

2. Components such as resistors, diodes, and tubular capacitors are available in “vertical” and “horizontal” installation methods

3. The grounding point of the circuit of the same level should be as close as possible, and the power filter capacitor of the circuit of this level should also be connected to the grounding point of this level

4. The total ground wire must be arranged in strict accordance with the principle of high-frequency-medium-frequency-low-frequency first-level ground in the order of weak current to strong current

5. Strong current leads (common ground wire, power amplifier power lead, etc.) should be as wide as possible

6. The traces with high impedance can be as short as possible, and the traces with low impedance can be longer

Abstract:Everyone knows PCB, so do you understand the wiring in PCB design? wiring in PCB design can be described as a basic course for every electronic engineer, but often everyone only pays attention to wiring and ignores the wiring arrangement between the components in the PCB. The following 6 points of knowledge for your reference:

1.No cross circuit is allowed in the pcb printed circuit boards，For lines that may cross, you can use “drilling” and “winding” to solve them. That is, let a certain lead “drill” through the gap under other resistors, capacitors, and triode pins, Or “wind” from  RC Jet one end of a lead that may be crossed. In special circumstances, if the circuit is very complicated, to simplify the design, it is also allowed to use a wire to bridge the cross circuit problem.

2.Components such as resistors, diodes, and tubular capacitors are available in “vertical” and “horizontal” installation methods. The vertical type refers to the installation and welding of the component body perpendicular to the pcb printed circuit board, which has the advantage of saving space. The horizontal type refers to the installation and welding of the component body in parallel and close to the pcb printed circuit board, and its advantage is that the mechanical strength of the component installation is better. For these two different mounting components, the component hole pitch on the pcb printed circuit board is different.

3.The grounding point of the circuit of the same level should be as close as possible, and the power filter capacitor of the circuit of this level should also be connected to the grounding point of this leve. In particular, the grounding points of the base and emitter of the transistor of this level should not be too far apart, otherwise the copper foil between the two grounding points will be too long, which will cause interference and self-excitation. Using such a “one-point grounding method” circuit will work better. Stable and not easily self-excited.

4.The total ground wire must be arranged in strict accordance with the principle of high-frequency-medium-frequency-low-frequency first-level ground in the order of weak current to strong curren,You must not just turn around and connect randomly, and you would rather have a longer connection between levels, and you must also abide by this rule. In particular, the grounding arrangement requirements of the frequency conversion head, regeneration head and frequency modulation head are more stringent. If improperly, it will self-excite and make it unable to work. High-frequency circuits such as FM heads often use large-area surrounding ground wires to ensure a good shielding effect.

5.Strong current leads (common ground wire, power amplifier power lead, etc.) should be as wide as possible, In order to reduce the wiring resistance and its voltage drop, the self-excitation caused by parasitic coupling can be reduced.

6.The traces with high impedance can be as short as possible, and the traces with low impedance can be longer, Because high impedance traces are easy to whistle and absorb signals, causing circuit instability. The power cord, ground wire, base trace without feedback components, emitter lead, etc. are all low impedance traces. The base trace of the emitter follower and the ground wire of the two channels of the radio must be separated, each forming one path. , Until the end of the function is combined again, if two ground wires are connected back and forth, it is easy to produce crosstalk and reduce the degree of separation.

The above is a summary of the experience of the wiring arrangement between the various components wiring in PCB design of the PCB, I hope it will be helpful to everyone.