FPC circuit board impedance refers to the parameters of resistance and reactance, which hinder the AC power supply. Impedance is often represented by Z, which is a complex number. The real part is called resistance, and the imaginary part is called reactance. The blocking effect of capacitance on alternating current in the circuit is called capacitive reactance, the blocking effect of inductance on alternating current in the circuit is called inductive reactance, and the blocking effect of capacitance and inductance on alternating current in the circuit is called reactance.
The unit of impedance is ohm. In FPC circuit board with resistance, inductance and capacitance, the blocking effect on AC is called impedance. FPC circuit board impedance includes characteristic impedance, differential impedance, odd mode impedance, even mode impedance and common mode impedance. In FPC circuit board production, impedance processing is essential. The reasons are as follows:
- The FPC circuit board should consider the connection and installation of electronic components. After the connection, the conductivity and signal transmission performance should be considered. Therefore, the lower the impedance, the better. The resistivity should be less than 1&TIMes: 10-6 per square centimeter.
- FPC circuit board must go through the process of production, and the materials used in these processes must ensure low resistivity to ensure that the overall impedance of the circuit board meets the product quality requirements and can operate normally.
- There will be various signals transmitted in the conductors of the FPC circuit board. When the frequency must be increased to improve its transmission rate, if the circuit itself is different due to etching, stack thickness, wire width and other factors, it will cause changes in the impedance value, make its signal distorted, and lead to a decline in the use performance of the circuit board. Therefore, it is necessary to control the impedance value within a certain range.