It can be further concluded that characteristic impedance is closely related with substrate material (CCL material). Dielectric constant of insulating material ( ε r) ī. The figure below clearly demonstrates the meaning of each parameter.īased on the formula displayed above, it can be concluded that elements affecting characteristic impedance include:Ī. In which Z 0 refers to the characteristic impedance ε r to dielectric constant of insulating material h to the thickness of insulating material between traces and datum plane w to the width of traces t refers to the thickness of traces. A signal plane is set to be outer layer controlling impedance and insulating material used to separate the signal plane and its adjacent datum plane, which can be clearly seen in the image below.Ĭharacteristic impedance can be figured out through formula. With high characteristic impedance, surface microstrip has been widely applied in PCB fabrication. This article focuses on characteristic impedance control of multilayer boards with microstrip structure. Consequently, transmission signals can be achieved integrally, reliably and accurately without interference or noise. One word, a circuit board will never achieve conformance to requirement unless both requirements are met.Ĭircuit performance provided by PCBs has to ensure reflection won't take place during signal transmission process signals keep integrated transmission loss be reduced with impedance matching achieved. It also should determine that characteristic impedance must never go beyond regulated range on the other hand. In other words, electrical test implemented on PCBs responsible for transmitting high-frequency signals and high-speed digital signals has to confirm the on, off and shortcut of circuits on the one hand. In order to be compatible with the development requirement like miniaturization, digitalization, high frequency and multiple functions, metal wires on PCBs (Printed Circuit Boards) as interconnect devices in electronic equipment not only determine the opening of current flow, but also play a role as signal transmission lines.
0 kommentar(er)
