Mirror-Symmetric Multilayer Circuit Module With Ground Through-Hole Shielding
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Solution Overview
Problem
The close proximity of components on circuit boards leads to significant ball side crosstalk in high-density and high-speed signal arrays, compromising signal integrity.
Innovation Solution
A multilayer board structure with mirror-symmetrical differential-signal portions and strategically arranged ground through holes to reduce magnetic field coupling and crosstalk, featuring a core layer with differential through-hole pairs and ground through holes surrounding them, connected to a main ground for effective shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If components are arranged closer to improve integration level, then device complexity is reduced and productivity is improved, but ball side crosstalk increases and signal integrity deteriorates
Solution Approach 1:
Ground through-holes are introduced as intermediary elements between differential signal lines to shield and isolate them from crosstalk. These ground via holes act as mediators that provide electromagnetic shielding without requiring increased spacing between signal components, thus maintaining high integration while improving signal integrity
Solution Approach 2:
The solution transitions from two-dimensional planar spacing to three-dimensional vertical shielding by utilizing ground through-holes that extend through the PCB layers. This dimensional change allows ground shielding structures to be inserted vertically between signal layers, providing crosstalk protection without consuming horizontal space that would reduce integration density
2Reliability
If ground through holes are added to reduce crosstalk, then signal integrity is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The ground shielding system is segmented into discrete ground through-holes distributed at specific intervals along the differential signal paths. This segmentation allows the shielding function to be implemented in a modular fashion, where only necessary locations require ground via holes, balancing effectiveness with structural simplicity
Solution Approach 2:
The ground through-holes serve multiple functions simultaneously: they provide electromagnetic shielding for crosstalk reduction, establish reference planes for signal integrity, and contribute to overall ground connectivity. This multi-functionality reduces the need for separate dedicated shielding structures, thereby simplifying the overall device complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively minimizes ball side crosstalk, maintaining signal integrity in high-density and high-speed signal transmissions on circuit boards.
Implementation Method 1
a plurality of first ground through holes arranged at intervals to surround the first differential through-hole pair, and electrically connected to the main ground
Data Source
AI summary
A circuit board device includes a multilayer board structure, a main ground and a circuit module. The main ground is configured in the multilayer board structure. The circuit module includes two differential-signal portions. These differential-signal portions are all located on one core layer of the multilayer board structure. Each of the differential-signal portions includes a differential through-hole pair and a plurality of ground through holes, and these ground through holes are arranged at intervals to surround the differential through-hole pair, and are electrically connected to the main ground. The patterns of the differential-signal portions are mirror symmetrical to each other based on an imaginary mirror line therebetween, and the minimum linear distances from the differential-signal portions to the imaginary mirror line are equal to each other.