The commonly used 50Ω impedance on PCB is mainly because of its matching performance in high-speed signal transmission. When the signal passes through the transmission line in the PCB, there will be an impedance mismatch between the various parts. If the impedance does not match, it will cause signal reflection and reduce the signal quality. decline.

The use of 50Ω impedance can ensure that the signal reflection and loss are reduced as much as possible, and it can also improve the noise tolerance and interference suppression ability of the PCB transmission line. In addition, 50Ω impedance is also a relatively common standardized impedance value, which is easy to purchase and cost control.

Generally speaking, the main reason for choosing 50Ω impedance is to ensure the quality of high-speed signals during transmission and to achieve the best signal transmission effect.

There are six main reasons why 50Ω impedance is commonly used on PCBs:

1. Consistency of signal transmission: 50Ω impedance can match the characteristic impedance of commonly used high-speed signal transmission line materials, and can ensure that the signal has a consistent impedance value on the entire transmission line, thus avoiding signal reflection and distortion in the circuit.

2. Improve signal integrity: Using 50Ω impedance can reduce the loss and noise tolerance of PCB transmission lines, thereby improving signal integrity and anti-interference.

3. Standardized impedance: 50Ω impedance is a standardized impedance value that is very popular in PCB design. At the same time, it is also easy to source and relatively low cost.

4. It can be easily connected: 50Ω impedance matching usually includes standard components such as plugs and sockets. This allows the PCB designer to more easily connect to other devices, test equipment, and instruments during the routing process.

5. Relatively reliable analog environment: 50Ω impedance is considered a suitable PCB field from mainly analog environment to mixed analog/digital environment.

6. Easier process and testing: Usually some special techniques are used in PCB manufacturing, such as buried holes, blind buried holes, etc. The 50Ω impedance makes these techniques more convenient to implement and is relatively easy to manufacture and test.

In summary, the use of 50Ω impedance in PCB design can effectively improve the signal transmission effect, and it has the advantages of standardization, easy connection, and reliable simulation environment, process and testing.