The impedance of the PCB circuit board of the smt patch factory usually refers to the parameters of resistance and reactance, which hinder the alternating current; generally, in the process of producing the PCB circuit board in the smt process workshop, impedance processing is essential, so why does the PCB board need impedance? The reasons can be summarized as follows:

1. The PCB circuit board (bottom) should consider the installation of electronic components, and consider the conductivity and signal transmission performance after plugging and unplugging. Therefore, the lower the impedance, the better, and the resistivity should be less than 1&TImes; 10 per square centimeter. -6 or less.

2. During the production process of the smt process workshop of the chip processing factory, the PCB board must undergo processes such as copper sinking, electroplating tin (or electroless plating, or thermal spray tin), and connector welding. The materials used in these links must be guaranteed. Low resistivity can ensure that the overall impedance of the circuit board is low, meet the product quality requirements, and can work normally.

3. The tin plating of the pcb is the most prone to problems in the production of the entire pcb circuit board, and it is the key link that affects the impedance. The biggest defect of the electroless tin plating layer is easy discoloration (easy oxidation or deliquescence), poor solderability, which will make the PCB circuit board difficult to solder, and the impedance is too high, resulting in poor conductivity or unstable performance of the entire board.

4. There will be various signals in the conductors of the PCB circuit board produced by the PCB board manufacturer. In order to increase its transmission rate, its frequency must be increased. Different factors such as width can cause changes in impedance values, distorting the signal, resulting in a degradation in the performance of the pcb circuit board. Therefore, the smt process operation needs to control the impedance value within a certain range to meet the standard.