PCB Signal Routing Structure for Crosstalk Reduction in Dense BGA Layouts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Dense wiring in circuits leads to significant interference (crosstalk) due to limited circuit wiring area, which existing technologies struggle to effectively manage without increasing the wiring area.
Innovation Solution
A circuit structure utilizing microstrips and striplines, combined with ground vias, to connect transceiving and control circuits, where microstrips with shortest lengths are used directly, and longer composite conductive lines employ striplines, with additional ground vias placed between vias to reduce crosstalk without increasing wiring area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If wires are compressed densely to reduce wiring area, then the circuit wiring area is reduced, but the crosstalk between wires increases significantly
Solution Approach 1:
The patent transitions from planar microstrip transmission lines to three-dimensional stripline structures by routing signals through internal conductive layers and via holes. This vertical dimensionality change allows wires to be stacked in different layers, reducing lateral spacing requirements while maintaining signal integrity and minimizing crosstalk through increased vertical separation and ground shielding.
Solution Approach 2:
The patent introduces ground conductors as intermediary elements between signal-carrying wires. These ground planes and ground vias act as shields that electrically isolate adjacent signal lines, reducing electromagnetic coupling and crosstalk. The ground intermediaries provide reference potentials and absorb stray electromagnetic fields between densely packed signal traces.
2Object-generated harmful factors
If ground vias are added between vias to reduce crosstalk, then the crosstalk is reduced, but the device complexity increases
Solution Approach 1:
The ground vias serve multiple functions simultaneously: they provide electrical connection between different conductive layers, act as electromagnetic shields to reduce crosstalk, establish reference ground potentials, and provide return current paths. This multi-functionality reduces the need for separate dedicated shield structures, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent combines ground vias with the existing via structure used for signal transmission. Rather than adding completely separate shielding elements, the ground vias are integrated into the same via holes and conductive layer system, sharing fabrication processes and structural space. This merging approach minimizes additional manufacturing steps and structural complexity.
Data Source
AI summary
A circuit structure includes a circuit board, microstrips, a stripline, and vias. The circuit board includes conductive levels. A first and second transceiving circuits are disposed on a first conductive level. A first microstrip is disposed on the first conductive level, and configured to couple a first pin of the first transceiving circuit to a second pin of the second transceiving circuit. A second and third microstrips are disposed on the first conductive level, and coupled to a third pin of the first transceiving circuit and a fourth pin of the second transceiving circuit, respectively. The stripline is disposed on a second conductive level. A first and second vias cross the first and second levels, and couple the second and third microstrips to the stripline. The first and third pins are an inner and outer pins of a front line of a BGA of the first transceiving circuit, respectively.