Printed Circuit Board Slotted Conductive Posts for Impedance Continuity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The impedance discontinuity between differential signal holes and differential lines in high-speed printed circuit boards leads to increased insertion loss, return loss deterioration, and fluctuation, especially with smaller diameter signal holes used in high-speed interconnect channels.
Innovation Solution
Incorporating slotted conductive posts between differential signal holes to increase the diameter of the holes perpendicular to the board thickness, reducing parasitic inductance and impedance, thereby improving impedance continuity and reducing insertion loss and fluctuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the diameter of differential signal holes is reduced to accommodate smaller package pitch, then the capacity and integration of the printed circuit board is enhanced, but the impedance discontinuity between differential signal holes and differential lines increases, leading to larger insertion loss and return loss deterioration
Solution Approach 1:
The patent introduces slotted conductive posts that extend in the thickness direction (Z-axis) of the board, creating a three-dimensional impedance matching structure. This vertical dimension allows the conductive posts to bridge the impedance discontinuity between differential signal holes and lines without increasing the horizontal footprint, thus maintaining high-density packaging while improving impedance continuity.
Solution Approach 2:
The slotted conductive posts act as intermediary elements positioned between the differential signal holes and differential lines. These posts serve as impedance matching transformers, gradually transitioning the impedance from the high-impedance small holes to the lower-impedance lines, thereby reducing insertion loss and return loss deterioration.
2Productivity
If the diameter of differential signal holes is reduced, then the package pitch can be decreased for higher integration, but the parasitic inductance of the differential signal holes increases, worsening impedance continuity
Solution Approach 1:
By extending conductive posts in the thickness direction, the patent creates additional current paths that reduce parasitic inductance. The vertical conductive posts provide low-inductance connections that bypass the harmful inductance of the small-diameter holes, enabling higher integration without the usual inductance penalties.
Solution Approach 2:
The slotted conductive posts change the electrical parameters of the signal path by providing alternative current flow routes. This modifies the inductance and capacitance distribution along the signal path, reducing parasitic inductance while maintaining the small hole diameter for high integration.
Data Source
AI summary
The present application relates to a circuit technology, and discloses a printed circuit board, including: a board body portion comprising a plurality of core boards and a plurality of dielectric layers, the plurality of core boards including a plurality of conductor layers, and the plurality of conductor layers including a differential signal transmission layer located on a surface layer of the board body portion and a differential signal line out layer located on an inner layer of the board body portion; two opposite differential signal holes located on the board body portion, the two differential signal holes being passed sequentially from the differential signal transmission layer to the differential signal line out layer through at least a portion of the core boards and connect the differential signal transmission layer to the differential signal line out layer; and two slotted conductive posts located between the two differential signal holes.