Description
The presence of common–mode noise in differential lines is a major contributor to signal integrity problems in high–speed digital systems. Common–mode noise is typically excited by skew. It can occur due to timing mismatches at the driver, length mismatches due to routing constraints, or phase velocity mismatches due to inhomogeneous dielectrics with fiber–weave effect. Common mode noise results in increased crosstalk and electromagnetic interference on packages and boards. The designed filter is applicable for the stripline–type differential lines and the performance is enhanced by adjusting the ground via pitch to create resonant planes with a high-impedance current return path for common-mode signals. The time domain characterization of the filter has been performed to investigate the differential signal integrity of the system. The full wave simulation results and measurement results after de-embedding have been compared to examine the consistency between them.
