Non-Uniform SMT Pad Layout for Resonance Shift in Connectors
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Solution Overview
Problem
High-speed SMT connectors and cables suffer from parasitic effects due to exposed conductive regions on pads, leading to signal quality degradation and unwanted resonances, which current methods to mitigate these issues are costly and mechanically unstable.
Innovation Solution
Designing SMT connectors with shortened unused portions of pads and pads to shift resonance frequencies away from signal frequencies, and using longer ground strips to maintain mechanical stability and reduce transmission line effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SMT connectors are used with standard pad designs, then manufacturing is simple and cost-effective, but exposed conductive regions cause parasitic effects and signal quality degradation
Solution Approach 1:
The patent extracts and removes the harmful exposed conductive regions from the pad design by implementing complete pad coverage with conductive material. The pad is designed to extend fully under the component, eliminating the exposed regions that cause parasitic effects and resonances.
Solution Approach 2:
The patent changes the geometric parameters of the pad by increasing its size to achieve complete coverage. The pad dimensions are adjusted so that the conductive material extends to the edges of the pad, transforming the pad from a design with exposed regions to one with full coverage, thereby eliminating parasitic effects.
2Reliability
If pad designs are modified to eliminate exposed conductive regions, then parasitic effects are reduced, but manufacturing complexity and cost increase
Solution Approach 1:
The complete pad coverage design serves multiple functions simultaneously: it eliminates parasitic effects, provides mechanical stability, and maintains ease of manufacture. The same pad structure that prevents resonant stubs also ensures proper soldering and mechanical attachment, making the solution universally beneficial without trade-offs.
3Reliability
If conventional pad designs are used, then manufacturing is straightforward, but unwanted resonances occur at signal frequencies
Solution Approach 1:
The patent converts the potentially harmful exposed conductive regions into beneficial complete pad coverage. By extending the conductive material to the edges of the pad, the design transforms what would be resonant stubs into non-resonant structures, effectively using the pad's edge geometry to prevent unwanted resonances at signal frequencies.
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
Improves signal integrity by reducing unwanted resonances and insertion loss while maintaining mechanical stability, without increasing manufacturing costs.
Implementation Method 1
shortened unused portions of pads and pads to shift resonance frequencies away from signal frequencies
Implementation Method 2
using longer ground strips to maintain mechanical stability and reduce transmission line effects
Data Source
AI summary
A high-speed transmission circuit comprises, as part of a signal path, a connector pin disposed on a pad that comprises an unused pad region. The unused pad region is not considered part of the signal path but is part of a resonant sub-circuit. In various embodiments, by properly adjusting the dimensions of the pad region and other structures in the high-speed transmission circuit, resonant frequencies of the sub-circuit are shifted to a frequency range that is outside of the frequency range of interest in the signal path, thereby, reducing insertion loss and increasing signal integrity without compromising mechanical stability.