Why must the USB4 and Thunderbolt 5 high-speed interconnect use 90Ω ultra-fine coaxial cable束

With USB4 and Thunderbolt 5 reaching 40Gbps to 80Gbps and even higher bandwidths, high-speed interfaces have put forward far more stringent requirements for cables than ever before. Traditional multi-strand cables can no longer guarantee signal stability, and 90Ω differential ultra-fine coaxial cables have therefore become the mainstream solution for high-speed transmission. It is more suitable for high-bandwidth scenarios in terms of structure, electrical performance, and anti-interference ability, and is the key foundation for current high-speed interconnects.

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Part 1: High-Speed Characteristics of USB4 and Thunderbolt 5

USB4, by integrating USB and Thunderbolt technologies, achieves the highest transmission speed of 40Gbps, and supports video output and power integration, aiming to perform multi-functional transmission through a single cable. Thunderbolt 5 further increases the bandwidth to 80Gbps, and can reach 120Gbps in specific modes to meet the needs of professional graphics, high-performance computing, and future immersive devices. Higher bandwidth means more stringent requirements for signal integrity, and also makes the cable a key link in influencing system stability.

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The necessity of 90Ω differential impedance

USB4 and Thunderbolt series interfaces both rely on high-speed differential signals, and the impedance of the differential pairs must be precisely matched to the protocol specifications to avoid reflections, crosstalk, and signal distortion. A 90Ω impedance not only ensures interface compatibility but also maintains lower error rates and more stable link performance in high-speed environments. For high-speed transmission, impedance control is not an option but a fundamental requirement for system-level reliability.

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Section 3: Performance Advantages of Ultra-Fine Coaxial Beam

Extremely thin coaxial cables adopt coaxial structure, which has stronger shielding ability, smaller diameter, and higher flexibility, allowing for high-density wiring in limited spaces. They can maintain consistent impedance and extremely low loss in high-speed interfaces, making them suitable for short-distance high-bandwidth applications such as notebook expansion, VR/AR interfaces, expansion docks, and high-performance peripheral connections. In multi-functional cables that carry data, video, and power, the extremely thin coaxial structure can significantly reduce noise and enhance anti-interference ability, ensuring the entire link remains stable under high-bandwidth conditions.

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Under the continuous upgrade of high-speed interfaces such as USB4 and Thunderbolt 5, the 90Ω differential ultra-thin coaxial cable bundle has become the industry's recognized optimal interconnect solution. It not only meets the needs of high-speed signal transmission but also provides a reliable, low-loss, and anti-interference cable structure in limited space.

I am[Suzhou Huichengyuan Electronic Technology],Focused on the design and customization of high-speed signal cable harnesses and ultra-fine coaxial cable harnesses, providing customers with professional interconnection solutions for future high-speed interfaces. For more information, please contactManager Zhang: 18913228573 (same as WeChat)。