Characteristics and impedance control of FPC impedance board of Shenzhen Flexible circuit Board

According to the transmission theory of signal, the signal is a function of time and distance variables, so the signal may change at every part of the line. Thus determine the ac impedance of the wire, that is, the change in voltage

And the ratio of the current change is the Characteristic Impedance of the transmission line: the Characteristic Impedance of the transmission line is only related to the characteristics of the signal line itself. In a real circuit, a wire

The intrinsic resistance value is smaller than the distributed impedance of the system, especially in high-frequency circuits, where the characteristic impedance is mainly determined by the distributed capacitance of the wire and the distributed impedance of the distributed inductance of the wire. Ideal transmission line

The characteristic impedance depends only on the unit distributed capacitance and unit distributed inductance of the wire.

There will be all kinds of signal transmission in the conductor of the FPC of the flexible circuit board, when the transmission rate must be improved and its frequency, if the line itself is not due to etching, lamination thickness, wire width and other factors

At the same time, the impedance value will change and the signal will be distorted. Therefore, the impedance value of the conductor on the high-speed circuit board should be controlled within a certain range, known as "impedance control". The flexible circuit board is affected

The impedance factors of FPC impedance board wiring mainly include the width of copper wire, thickness of copper wire, dielectric constant of medium, thickness of medium, thickness of pad, path of ground wire, wiring around the wire, etc.

Therefore, when designing FPC impedance board of flexible circuit board, it is necessary to control the impedance of the line on the board, so as to avoid signal reflection and other electromagnetic interference and signal integrity problems as far as possible, and ensure

Practical stability of FPC impedance board with flexible circuit board.