BGA Contact Array Asymmetric Pin Layout for Crosstalk Reduction
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Solution Overview
Problem
High-density arrangement of differential pins in BGA contact devices leads to signal cross-talk due to close proximity, which is mitigated by adding shield pins, but this reduces pin density.
Innovation Solution
A contact device with a grid arrangement of contacts, where each differential wire pair is connected to a contact pair with a straight line orientation different from adjacent pairs, reducing cross-talk while maintaining high density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If differential pins are arranged in a straight line with high density, then pin density is improved, but signal cross-talk increases
Solution Approach 1:
The patent applies asymmetry by arranging contact pairs in a staggered pattern rather than straight lines. Each contact pair is offset from adjacent pairs, creating an asymmetric layout that increases spacing between differential pins and reduces electromagnetic coupling, thereby reducing signal cross-talk while maintaining high pin density.
Solution Approach 2:
The patent transitions from one-dimensional straight-line arrangements to two-dimensional staggered arrangements. By utilizing the additional spatial dimension, the contact pairs are distributed more effectively across the contact array, increasing inter-pair spacing without reducing overall density, thus mitigating cross-talk.
2Reliability
If shield pins are arranged between differential pins to decrease cross-talk, then signal integrity is improved, but pin density decreases
Solution Approach 1:
The patent extracts the shielding function from dedicated shield pins and integrates it into the differential pair structure itself. By using the return path of adjacent differential pairs as natural shields, the design eliminates the need for separate shield pins, maintaining signal integrity through the differential signaling mechanism while preserving high pin density.
Solution Approach 2:
The patent makes the differential pair contacts serve multiple functions: signal transmission and mutual shielding. Each contact pair not only transmits differential signals but also acts as a shield for adjacent pairs through its return current path, eliminating the need for dedicated shield pins and maximizing pin utilization.
Data Source
AI summary
A contact device including a contact array, in which contacts are arranged in a grid, and a plurality of differential wire pairs electrically connected to the contact array, wherein each differential wire pair is connected to a contact pair formed by two adjacent contacts in the contact array, and each contact pair is arranged such that a direction of a straight line connecting the two contacts therein is different from a direction of a straight line connecting the two contacts in a contact pair adjacent thereto.