Quality control of PCB circuit boards
The information comes from:the Internet posted on:2023-04-19
PCB circuit board impedance refers to the resistance and reactance parameters that hinder communication, and solving PCB impedance is crucial in production. The reasons are as follows:
1. PCB (bottom of circuit board) should consider the insertion and installation of electronic components. After blocking, consideration should be given to conductivity and signal transmission performance. Therefore, the smaller the impedance, the better. The resistivity should be less than one time per square centimeter; Less than 10-6
2. PCB circuit boards should be plated with copper, electroplated with tin (or chemically plated or thermally sprayed with tin), and in the manufacturing process of connector soldering, it is necessary to ensure the low resistivity of commonly used materials in these stages to ensure the overall low impedance of the circuit board, meet product quality requirements, and operate normally
3. Tin plating on printed circuit boards is not only a common problem in the entire manufacturing process of printed circuit boards, but also an important factor in determining impedance. The disadvantages of chemical tin plating [sensitive term] are easy discoloration (easy oxidation or deliquescence) and poor solderability, which makes the circuit board unable to be soldered, has high impedance, poor conductivity, or unstable overall circuit board performance
4. The conductor in the middle of the PCB will have various signal transmissions. In order to ensure transmission speed, due to etching, the impedance value of the circuit itself will increase, the thickness of the pressure layer, and different factors will change, which will distort the signal and affect the performance of PCB applications. Therefore, it is necessary to control the impedance value within a certain range.
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