PCB Differential Signal Routing to Prevent Crosstalk
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Solution Overview
Problem
In electronic apparatuses with increasing performance, differential transmission paths of different standards on a printed circuit board face interference due to varying characteristic impedances, leading to crosstalk and unnecessary radiation noises.
Innovation Solution
The solution involves arranging first and second terminals of electronic components on a printed circuit board such that the corresponding wiring patterns do not intersect, ensuring that differential signals with different characteristic impedances do not cross, thereby preventing crosstalk and reducing radiation noises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple differential transmission paths of different standards are mounted on the same printed circuit board to increase performance and added value, then the functionality and versatility of the electronic apparatus is improved, but interference and crosstalk occur due to different characteristic impedances
Solution Approach 1:
The printed circuit board is divided into multiple regions, with each region dedicated to a specific differential transmission path standard (e.g., USB region, HDMI region). This spatial segmentation isolates the different impedance environments, preventing interference between standards while maintaining the ability to support multiple standards on the same board.
Solution Approach 2:
Each differential transmission path region is designed with local impedance characteristics optimized for its specific standard. The wiring patterns, trace widths, and spacing are locally adjusted to achieve the required characteristic impedance for each standard (e.g., 90Ω for USB, 100Ω for HDMI), ensuring optimal signal quality without affecting other regions.
2Reliability
If wiring patterns are arranged to prevent crosstalk between different differential signals, then signal quality is improved, but the layout complexity and difficulty of routing increase
Solution Approach 1:
By dividing the board into distinct regions for different differential standards, the routing complexity is reduced. Each region can be routed independently with its own impedance requirements, avoiding the need to manage multiple impedance constraints simultaneously across the entire board.
Solution Approach 2:
The problem of preventing crosstalk between differential pairs of different standards is solved by transitioning from a two-dimensional planar routing challenge to a three-dimensional spatial organization. By vertically separating different standards into different regions or layers, the design simplifies the routing constraints while maintaining signal integrity.
Data Source
AI summary
An electronic apparatus that can prevent occurrence of crosstalk between different differential signals on a printed circuit board on which a wiring pattern of a differentially operated signal line is formed, and reduce unnecessary radiation noises. First and second wiring patterns are disposed on the printed circuit board and through which differentially operated signals are transmitted, and the first and second wiring patterns are electrically connected to first and second connection terminals, respectively. An electronic component is disposed on the printed circuit board, and includes first and second terminals electrically connected to the first and second wiring patterns, respectively. The first and second terminals of the electronic component are disposed on the printed circuit board, respectively, so that the first and second wiring patterns do not intersect each other.