QSFP-DD Backshell Rear PCB Pads for Four Cable Rows
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Standard QSFP-DD connectors are limited to inserting only three rows of twisted pairs of cables with gauges higher than 27 AWG due to vertical spacing constraints, preventing the addition of a fourth row without degrading bandwidth and data rates.
Innovation Solution
The design modifies the QSFP-DD connector backshell to accommodate a fourth row of cables by printing additional conductive pads along the rear edge of the PCB, allowing the insulation sleeve of the additional row to terminate and expose wires for alignment with conductive pads, enabling soldering and overlapping with existing rows while keeping the lower half of the sleeve below the PCB surface, thus optimizing vertical space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the backshell dimensions and PCB thickness are kept according to standard QSFP-DD specification, then the connector complies with the specification and maintains proper mating capability, but only three rows of twisted pairs of cables can be inserted due to vertical spacing constraints
Solution Approach 1:
The patent applies dimensionality change by moving the conductive pads for the fourth row from the top surface to the rear surface of the PCB. This spatial reconfiguration allows cables to approach the PCB from a different direction (from the rear rather than from above), effectively utilizing unused vertical space and enabling four rows of cables without increasing the backshell's overall height.
Solution Approach 2:
The patent segments the pad arrangement into multiple groups: pads for the first three rows remain on the top surface, while pads for the fourth row are placed on the rear surface. This segmentation allows different cable rows to be connected at different locations and angles, resolving the space conflict by distributing connection points across multiple surfaces of the PCB.
2Productivity
If a fourth row of cables is added to increase data transfer capability, then bandwidth and data rates are enhanced, but the vertical spacing between PCB and backshell sidewall is insufficient to accommodate the cable insulation sleeve
Solution Approach 1:
The patent resolves the vertical spacing constraint by changing the approach dimension. Instead of requiring vertical clearance above the PCB top surface, the solution allows cables to approach from the rear surface direction, utilizing the lateral depth of the PCB rather than its vertical clearance. This enables four rows of high-gauge cables without compromising the required vertical spacing for thermal and mechanical reasons.
Solution Approach 2:
The patent applies local quality by creating a localized pad structure on the rear surface of the PCB specifically for the fourth row of cables. This localized arrangement allows the fourth row to be accommodated in a region that would otherwise be unused, enabling high-gauge cables to be connected without requiring additional vertical space in the constrained backshell environment.
3Productivity
If the gauge of cables is increased to achieve higher data rates and bandwidth, then data transfer performance is improved, but the cable diameter increases making it difficult to fit four rows in the limited vertical space
Solution Approach 1:
The patent resolves the cable diameter conflict by changing the spatial arrangement from a purely vertical stacking approach to a multi-surface approach. High-gauge cables for the fourth row can be routed from the rear surface at an angle, allowing them to clear other cables and components without requiring reduced cable gauge. This maintains bandwidth performance while accommodating larger cable diameters in the limited backshell volume.
4Adaptability or versatility
If conductive pads are added on the rear edge of PCB to accommodate the fourth row, then four rows of cables can be inserted, but the complexity of PCB design and cable routing increases
Solution Approach 1:
The patent manages design complexity through segmentation by dividing the pad layout into distinct groups: three groups of pads on the top surface for the first three rows, and one group on the rear surface for the fourth row. This segmented approach organizes the increased complexity into manageable sections, making the PCB design and cable routing process more systematic and easier to implement despite the additional row.
Data Source
AI summary
A connector backshell for accommodating and protecting rows of twisted pairs of cables is provided. The backshell includes four sidewalls and a printed circuit board (PCB) with a first group of conductive pads printed on the top side of the PCB and located at the rear side of the PCB, for receiving rows of corresponding wires of insulated cables, to be connected to the conductive pads, such that one row is located below the PCB and the other rows are located on top of each other above the top surface of the PCB. A second group of conductive pads are printed on the bottom side of the PCB and located at the rear side of the PCB, for receiving corresponding wires of insulated cables, to be connected to the conductive pads, such that at least one row is located below the PCB.