Project Analog - March 2008 - (Page 14)

these early solutions have established the feasibility of transporting 10-gbit data over 100 m of UtP cable, but it will require another generation or two to produce solutions with the potential for widespread adoption. choice for interconnecting servers over the relatively short distances spanned. Copper interconnects using unshielded twisted pair cable (10GBASE-T) are expected to eventually also dominate 10-Gbit Ethernet data center applications, and first-generation solutions are available now. These early solutions have established the feasibility of transporting 10-Gbit data over 100 m of UTP cable, but it will require another generation or two to produce solutions with the potential for widespread adoption. In the meantime, other interconnect technologies, both optical and copper, should be considered. Copper phys 10GBASE-CX4. Ideal for high-performance datacenters, CX4 offers low cost and zero added latency over short distances. The relatively bulky twinax cable, similar to that used for InfiniBand, transports XAUI signals up to 15 m, or further with added equalization, and offers the lowest per port cost at the expense of range. The CX4 connector can also provide power through one of its pins. Optical cables are available that have CX4 connectors and that provide the electrical-to-optical and optical-to-electrical conversion in the cables themselves, allowing reaches well beyond 15 m. 10GBASE-T. This newly released standard uses a familiar and compact RJ-45 connector and inexpensive Cat6 cable to transmit up to 55 meters, and supports autonegotiation between Gbit and 10 Gbit. Using the new partitioned, augmented Cat6 or “6a” cable specification, which is still in draft form and is designed to reduce crosstalk between UTP cables, 10GBASE-T signals can be transported up to 100 meters. Implementations of 10GBASE-T have been demonstrated by multiple vendors; however, it does have relatively high power consumption and several µs of latency, both of which are likely to be improved as components mature. This may be a good choice for enterprise Gbit Ethernet aggregation products. optiCal phys Optical fiber links represent an elegant solution for interconnectivity in the data center due to the small size and weight of the fiber, ease of cable management, long reach, low susceptibility to EMI, and low latency. Cost reductions have begun to make then a more competitive choice compared to copper (see Table 2). Parallel optics. A multi-fiber ribbon comprising four transmit and four receive fibers provides a lightweight, flexible cable with a CX4 connector, with about a 100-m reach. A relatively low-cost option when using 850 nm VCSEL optics, parallel optics offers low (but nonnegligible) power consumption and negligible latency. 10GBASE-SR. The “SR” designates “short range.” This standard specifies distances from 26 m over legacy 62.5 µm core MM fiber, to 86 meters on standard 50-µm core MM fiber, to 300 m using high-quality laser-optimized (OM3) MM fiber using 850-nm VCSEL technology. Contents Viewpoint Wireless Communication Using IrDA® Wireless Design Choices Advanced Communication Solutions for Lighting Analog news Microchip analog page Interface products overview Sample center microchipDIRECT Reference designs/ app notes Technical training 14 · ProjeCt ANALog · mAr 08 http://www.microchip.com http://www.microchip.com/analog http://www.microchip.com/analog http://www.microchip.com/interface http://www.microchip.com/interface http://sample.microchip.com/Default.aspx?testCookies=true http://www.microchipdirect.com/catalogselection.aspx?returnURL=default.aspx http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1469&filter1=function&redirects=appnotes http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1469&filter1=function&redirects=appnotes http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1423

Table of Contents Feed for the Digital Edition of Project Analog - March 2008

Project Analog - March 2008 Contents Viewpoint About Project Analog Sponsor Wireless Communication Using the IrDA® Standard Protocol Wireless Design Choices Advanced Communication Solutions for Lighting Putting 10-GbE PHY Options Into Perspective Ease Into the Flexible CANbus Network Technology and Drivers for Mobile WiMAX Analog News—Analog News from Multiple Sources Enter to Win an iPhone Contact Project Analog Sponsor Treelink Microchip Advanced Parts Selector (MAPS)

Project Analog - March 2008

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