What is a characteristic impedance pcb board

Characteristic impedance refers to the resistance of the high-frequency signal or electromagnetic wave in the propagation process of the transmission signal line relative to a certain reference layer at a certain frequency, that is, the characteristic impedance, also called the characteristic impedance. It is equivalent to a vector sum of electrical impedance, inductive reactance, capacitive reactance, etc.

What is the significance of making a characteristic impedance pcb board?

Characteristic impedance is at the heart of solving signal integrity problems.

With the continuous development of pcb electronic products towards high frequency and high speed, the circuit performance provided by the PCB must ensure that the signal does not reflect during the transmission process, and the signal is kept intact and undistorted.

In order to ensure signal integrity, it is required that the characteristic impedance (Z0) of the signal line of the PCB must match the "electronic impedance" of the head and tail components; when electronic equipment such as computers and communication switches are in operation, the signals sent by the driving components need to pass through the PCB. The signal line reaches the receiving element.

Impedance - actually refers to the parameters of resistance and reactance, because the PCB circuit (board bottom) needs to consider the insertion and installation of electronic components, and consider the conductivity and signal transmission performance after insertion, so the lower the impedance, the better. The resistivity should be lower than the negative 6th power of 1×10 per square centimeter.

Under normal design components, the relationship of factors affecting impedance:

1. The thicker the dielectric layer, the greater the impedance value;

2. The larger the dielectric constant, the smaller the impedance value;

3. The thicker the copper foil, the smaller the impedance value;

4. The larger the line width, the smaller the impedance value;

5. The thicker the ink thickness, the smaller the resistance value.

The above is the introduction of the relevant knowledge of characteristic impedance pcb board, if you need it, you can contact us!