Forward-Soldered Flat Cable Layout to Prevent PCIe Stub Effects
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Solution Overview
Problem
The reverse soldering of PCIe bus connection wires causes signal attenuation and impedance mismatch due to extra signal paths and stub effects, which are exacerbated by the transition from PCIe 3.0 to the faster PCIe Gen5.
Innovation Solution
A bus connection wire forward soldering structure that includes a circuit board, flat cable, and fixing member, where the flat cable is attached to the circuit board with a forward soldering method, allowing the cable to be reversely folded and bent to extend along the same direction as the solder terminal, avoiding extra signal paths and stub effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If reverse soldering is adopted to allow reverse wiring of the flat cable, then the cable can be flexibly installed in the same extending direction, but signal attenuation and impedance mismatch occur due to extra signal paths and stub effects
Solution Approach 1:
The patent inverts the traditional reverse soldering approach by using forward soldering methodology. The flat cable is soldered in the forward direction (solder terminal facing the docking area along the outgoing line direction), but the cable body is routed to achieve reverse wiring functionality. This inversion of the soldering direction eliminates the stub effect while maintaining reverse wiring capability.
Solution Approach 2:
The patent introduces a folding section with first and second attaching sections that attach to opposite surfaces of the circuit board. This three-dimensional routing arrangement allows the cable to achieve reverse wiring functionality through spatial arrangement rather than through-planar reverse soldering, thereby avoiding signal degradation while maintaining design flexibility.
2Reliability
If forward soldering is used to connect the solder terminal to the solder area, then signal integrity is maintained, but the cable cannot be configured for reverse wiring
Solution Approach 1:
The patent uses a three-dimensional routing configuration with folding sections that attach to both surfaces of the circuit board. This spatial arrangement enables the cable to achieve reverse wiring functionality through 3D routing while maintaining forward soldering connections, thus preserving signal integrity while gaining wiring flexibility.
Data Source
AI summary
A bus connection wire forward soldering structure includes a circuit board, a flat cable and a fixing member, and the circuit board has a solder area, a docking area, first and second surfaces and an outgoing line direction. The solder area is disposed on the first surface, the flat cable includes a solder terminal, first and second attaching sections, a folding section and a main body section, the solder terminal faces the docking area and is electrically connected to the solder area, the folding section is connected between the first and second attaching sections, the main body section extends along the outgoing line direction, the fixing member covers the solder terminal, the folding section, the first and second attaching sections, the fixing member has a notch defined corresponding to the second surface and located at junction of the second attaching section and the main body section junction.