PCB circuit board impedance refers to the parameters of resistance and reactance, which have a blocking effect on AC power. In the production of PCB circuit boards, impedance processing is essential. Why do PCB circuit boards need to have impedance?

Why is impedance necessary for PCB circuit boards

In summary, there are several reasons for this:

1. The PCB circuit (bottom of the board) needs to consider the electronic components of the plug-in device, and after plugging, consider issues such as conductivity and signal transmission performance. Therefore, it is required that the lower the impedance, the better, and the resistivity should be less than 1& 1 per square centimeter; TImes； Below 10-6.

2. During the production process of PCB circuit boards, there are manufacturing processes such as copper deposition, electroplating tin (or chemical plating, or hot spray tin), and connector soldering. The materials used in these processes must ensure low electrical resistivity to ensure that the overall impedance of the circuit board meets product quality requirements and can operate normally.

3. Tin plating on PCB circuit boards is a common problem in the entire circuit board manufacturing process and a key link that affects impedance. The disadvantages of chemical tin plating are easy to color (such as oxidation or deliquescence), poor solderability, which can lead to difficulty in soldering circuit boards, high impedance, poor conductivity, or unstable overall board performance.

4. There are various signal transmissions in the conductors of PCB circuit boards. In order to improve their transmission rate, it is necessary to increase their frequency. If the circuit itself is affected by factors such as etching, stack thickness, and wire width, the impedance value will change, causing signal distortion and a decrease in the performance of the circuit board. Therefore, it is necessary to control the impedance value within a certain range.

Article source: PCB manufacturerhttp://www.yonghongpcb.com/