High-density pluggable I/O interface solutions for high-speed applications

High-density pluggable I/O interface solutions for high-speed applications

As a high-speed I/O connection in network, storage and telecommunications equipment applications, the advantages of pluggable I/O interfaces are very obvious. It features standard device I/O interfaces, pluggable modules and flexible cable connections, and the choice of fiber or copper links. It also supports multiple data transmission rates and multiple protocols such as Ethernet, Fibre Channel and InfiniBand. Therefore, integrators can use it to design cable structures according to different application requirements. Currently, the rapid growth of bandwidth demand for data communication equipment has prompted the rapid upgrading of pluggable I/O interfaces in order to achieve greater throughput in a smaller package.

At present, the small package hot plug (SFP) product line, including single-port and single-row stacked high-density multi-port SFP shielding cages, has matured and is widely used in industry. Their motherboards contain high-speed signal connectors and electromagnetic interference shielding cages. With the increasing market requirements for functions and data transmission rates, Tyco Electronics provides users with new SFP solutions, including: integrated light pipes for port indication, improved connectors to improve signal integrity, enhanced EMI shrapnel to reduce electromagnetic interference, and cross-type heat sink technology for thermal management.

Since the data transmission rate reached 10Gb per second, Tyco Electronics has been actively developing the 10Gb serial standard (XFP) and the 10Gb standard X2 MSA based on XAUI. XFP achieves a single-channel transmission rate of 10Gbps, but also poses new challenges to signal integrity and EMI electromagnetic interference. This problem can eventually be solved by using low-loss connectors and conductive gaskets. The increase in protocol speed has promoted the development of the SFP+ interface and increased SFP's support for applications such as 8X Fiber Channel and 10G Ethernet standards to 10Gbps. The control of EMI electromagnetic interference at high data transmission rates has also been solved by enhanced EMI shrapnel and rubber gaskets. Similar to SFP, SFP+ also has single-port and single-row stacked high-density multi-port shielding covers to choose from.

In order to meet the market demand for higher density, high-speed pluggable solutions, the Quad SPF interface (QSFP) came into being. This 4-channel pluggable interface has a transmission rate of 40Gbps. Many mature key technologies in XFP are applied to this design.

QSFP can be used as a fiber solution, and its speed and density are better than the 4-channel CX4 interface. Since it can support four channels of data transmission at a speed of 10Gbps per channel under the same port volume as XFP, the density of QSFP can reach 4 times that of XFP products and 3 times that of SFP+ products. The QSFP interface with 4 channels and higher density than CX4 has been adopted by the InfiniBand standard.

Figure 1: Components of a QSFP application.

Tyco Electronics has developed direct-connect cable assemblies using the above pluggable interface. Direct-connect cables abandon the traditional receiver and no longer connect the optical or copper cable assembly to the system through the receiver, but are programmed to meet the different application requirements of the terminal. For short-distance applications, copper cables are an economical and practical solution. It can be set to active or passive equalization without equalization. Tyco Electronics can now provide active PARALIGHT optical cables for QSFP interfaces without the use of receivers, fiber interfaces and other related equipment.

Figure 1 shows a QSFP application. Typically, the components of a pluggable I/O interface include:

* One motherboard connector

* A shielding cage or rail to control EMI interference and indicate contact with the plug

* A mating plug. Can be a pluggable receiver or a direct attach cable assembly. Pluggable receivers require a mating cable assembly.

* Accessories include heat sinks, light pipes, dust covers, and EMI shields.

A device can be configured with I/O ports in a variety of ways to achieve the goal of increasing density. As shown in Figure 2, adjacent ports in a parallel cage share the same side wall, so each port is smaller on the base plate and arranged more tightly than a single row. Stacked ports are arranged just as tightly as parallel, while adding an additional row of ports in the vertical direction. Stacked cages have an integrated connector that is fixed to the PCB by crimping. Another common method is to have ports on both sides of the PCB, usually called "back-to-back". In these configurations, surface mount connectors are used to improve electrical performance. For specific examples, please refer to the introduction of SFP+.

Figure 2: Comparison of four different I/O port configurations.

To demonstrate the speed/density ratio that is achievable today, we configured parallel 1x3 QSFP cages in a “back-to-back” configuration to fit 36 ​​QSFP ports into a 1U chassis, providing 144 channels of data transmission performance at up to 10Gb/s per channel in a 1U chassis.

Tyco Electronics has established an excellent R&D team in Shanghai for high-speed and high-density interface products, and most of our high-speed and high-density interface products are also produced in China. Therefore, we can not only provide customers with high-speed and high-density interface products that meet standards or are commonly used in the market, but also provide Chinese customers with a full range of customized product services in China quickly and effectively according to their special requirements.

Tyco Electronics has always been a leader in the research of pluggable I/O standards. We will continue to work on new pluggable interface standards to meet the market's growing demand for communication bandwidth. And, as an industry leader, we will continue to provide data integrity and EMI interference protection designs at high data rates.

For a comprehensive overview of TY Electronics' pluggable interface developments, or to search data sheets and parts, visit www.tycoelectronics.com/products/pluggableIO. For technical support, visit TY Electronics' technical support website at www.tycoelectronics.com/help.

About Tyco Electronics

TE Connectivity is a leading global supplier of electronic components, network solutions, submarine communication systems and specialty products, with sales revenue of $14.4 billion in more than 150 countries in the world in fiscal 2008. The products we design, manufacture and sell cover a wide range of industrial fields, including automobiles, data transmission systems and consumer electronics, communications, aerospace, defense and marine, medical, power and lighting. We have about 7,000 professional engineers, and a global network of production plants, sales and customer service. TE Connectivity's commitment is the advantage of our customers.

As a global enterprise, TE entered China in 1989 and opened its first factory in Shanghai. Currently, TE has established 16 production bases in China and provides services to customers through sales offices in 15 cities across the country. Its sales in fiscal 2008 reached US$1.8 billion, accounting for 12% of its global total revenue.