The following are some methods to avoid the problem of impedance mutation of inter-layer connections when designing multi-layer stacking:
1.Accurate wiring planning: Carefully design the wiring direction and width of each layer, maintain consistency, and reduce the factors of impedance change.
2.Strictly control the via parameters: Ensure that parameters such as the diameter, length, and plating thickness of the via meet the impedance requirements to avoid impedance discontinuity caused by the via.
3.Use a matched transmission line structure: Adopt an appropriate transmission line type, such as a microstrip line or a stripline, and design according to its characteristics.
4.Uniform thickness of the inter-layer dielectric: Keep the thickness of the inter-layer dielectric uniform among all layers to avoid impedance fluctuations caused by thickness changes.
5.Close combination of the signal layer and the reference layer: Make the signal layer close to a stable reference layer (such as the ground layer or the power supply layer) to maintain a relatively stable impedance environment.
6.Simulation and verification: In the design process, use simulation tools to simulate and analyze the impedance of inter-layer connections, and timely discover and adjust the places where impedance mutation may occur.
7.Follow the impedance control standard: Design and control impedance according to the established industry standards or enterprise internal specifications.
8.Consider the material characteristics: Fully understand the influence of the dielectric constant and other characteristics of the PCB material on the impedance, and choose the appropriate material.
9.Optimize the component layout: Reasonably arrange the position of components to avoid greater interference to the impedance of inter-layer connections caused by components.
10.Conduct impedance testing: Conduct impedance testing on the finished product after production to ensure that the actual impedance meets the design requirements.