Staggered Differential Pad Layout for EMI Suppression
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Solution Overview
Problem
Conventional electronic assemblies face challenges in effectively suppressing electromagnetic interference (EMI) and ensuring accurate timing positioning during high-speed signal transmission, particularly due to the limitations of single-ended signal transmission technologies.
Innovation Solution
The electronic assembly features a circuit board with a unique layout of staggered differential signal pads arranged in pairs, where the center extension lines of adjacent pairs intersect at a symmetry line, and power pads replace some ground pads to prevent trace interference and provide a stable reference power source, enhancing signal transmission quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional single-ended signal transmission is used, then the circuit board layout is simple, but electromagnetic interference suppression capability deteriorates
Solution Approach 1:
The patent applies asymmetry by intentionally designing the circuit board layout to be non-symmetric, specifically positioning differential signal pad pairs at different distances from the reference plane. This asymmetric configuration creates unequal signal paths that help cancel electromagnetic interference through differential signaling, improving EMI suppression while maintaining manageable layout complexity
Solution Approach 2:
The patent transitions from conventional two-dimensional planar routing to a three-dimensional configuration by utilizing vertical spacing between the circuit board surface and the reference plane. This dimensional change allows for optimized signal paths and improved EMI suppression through controlled impedance design, addressing the contradiction between EMI performance and layout simplicity
2Measurement precision
If conventional parallel arrangement of differential signal pads is used, then manufacturing is easier, but timing positioning accuracy deteriorates
Solution Approach 1:
The patent employs asymmetric positioning of differential signal pad pairs relative to the reference plane, creating different path lengths for adjacent pairs. This asymmetric arrangement enables precise timing positioning by allowing independent optimization of signal paths, while the systematic nature of the asymmetry keeps manufacturing complexity manageable
Solution Approach 2:
The patent applies local quality by optimizing each differential signal pad pair's position and orientation individually based on its specific timing requirements. Each pair can have customized spacing and angular orientation from the reference plane, allowing precise timing control for high-speed signals while maintaining overall manufacturing feasibility through standardized processes
3Object-generated harmful factors
If traditional ground pad configuration is used, then the structure is simple, but trace interference increases
Solution Approach 1:
The patent extracts the ground reference function from traditional ground pads and replaces it with dedicated power pads connected to a reference plane. This separation eliminates ground loops and reduces trace interference by providing a clean, stable reference potential, while the simplified power pad structure actually reduces overall complexity compared to complex grounding schemes
Solution Approach 2:
The patent introduces power pads as an intermediary element between the signal traces and the reference plane. These power pads serve as intermediate connection points that provide stable reference potential without creating ground interference, effectively mediating between signal paths and reference structures to reduce trace interference
Data Source
AI summary
An electronic assembly includes a circuit board having a mounting surface and outer pads located on the mounting surface and staggered. The outer pads include pairs of differential signal pads arranged adjacent to each other including a first pair of differential signal pads and a second pair of differential signal pads. The first pair of differential signal pads and the second pair of differential signal pads are symmetrically arranged with respect to a symmetry line. A center extension line passing through the first pair of differential signal pads and a center extension line passing through the second pair of differential signal pads intersect at an intersection point on the symmetry line. The center extension line passing through the first pair of differential signal pads or the center extension line passing through the second pair of differential signal pads and the symmetry line are not perpendicular to each other.