Three Considerations for Designing Connectors and Cables for High-Speed Applications, The design challenge for connectors and cables for high-speed transmission applications is not only to transmit all the necessary data, but also to be able to transmit large amounts of data at faster speeds and therefore the design of connectors and cables should be carefully considered.
Designing connectivity solutions for specific data protocols requires optimizing the design of connectors and cables, and while they must work well together, the primary requirement for a functional solution is to have a device protocol or multiple for high-speed protocol connectors that can handle specific data, the protocol or protocols used will determine the number of contacts for each connector. Each protocol requires specific design rules for the connector.
Examples include having a specific connector configuration that provides USB 3.0 speeds, using materials designed to help reduce interference, and using a unique nine-pin configuration to reduce the physical connector size while still providing the data speeds required by military, medical and industrial companies. It is technically possible to run Ethernet through this connector because Ethernet requires fewer contacts than USB 3.0, but there are other available contact configurations specifically designed to maximize Ethernet data speeds. Since multi-protocol connectors still have high-speed capability, they simply combine all the relevant protocol-specific design rules in one connector.
The data speeds that connectors and their configurations must exceed, the construction of the cable itself plays a huge role in determining whether a connection solution can meet high-speed data requirements. Standard ISO/IEC 11801 specifies general telecommunications cabling systems (e.g. structured cabling) applicable to a wide range of applications, including analog and ISDN telephony, various data communications standards, building control systems and factory automation. Balanced cabling performance is defined by a set of multiple parameters related to insertion loss (IL), return loss (RL), near-end crosstalk (NEXT) and far-end crosstalk (FEXT). In ISO/IEC standards, structured cabling components (e.g., cables, connection hardware, and patch cords) are characterized by performance levels and collaborate to form links or channels described by performance levels. In the TIA standard, both components and cabling are characterized by performance classes. In addition, shielding plays an important role in data transmission speed, and ISO/IEC 11801:2002 aims to develop naming standards for shielded cables: U for unshielded, S for braided shield (outer layer only), and F for foil shield. These designations indicate the type of shielding or shielding used for overall cable protection and twisted pair (TP) or individually shielded twisted pair (TQ), and aid in cable selection.
When rugged interconnect solutions must achieve speeds (such as USB 3.0) that require testing both connectors and cables, most connector suppliers provide specific testing recommendations to avoid the iterative trials of testing connectors and cables together. Once the connectors and cables have been designed and optimized for the defined protocol, physical product prototypes need to be tested to verify complete characterization using a network analyzer. It is not impossible for connectors and cables to pass speed tests individually but fail together, so testing the complete assembly is critical. The physical testing of multiple connectors and cables can become cumbersome, so many companies turn to simulation software to find the right solution. Simulation software is a tool for this design process because it allows designers to verify the compatibility of the entire cable assembly with the target protocol and also allows immediate evaluation of the impact of design modifications in the time and frequency domains, resulting in optimized designs and connectors with a high level of confidence in matching the desired protocol.
Abstract: Designing connectors and cables for high-speed applications requires careful consideration of each part of the connectivity solution to achieve data rates in applications that require high-speed performance.