Gennum launches quad 10-Gbit/sec CDR

NOVEMBER 18, 2008 -- Significantly extending the performance and reach of high-performance computing and networking interconnects, Gennum Corp. has launched the GN2406, which it calls the industry's first quad 10-Gbit/sec clock and data recovery (CDR) device aimed at optical modules, backplanes, line cards, and active copper cable assemblies.

NOVEMBER 18, 2008 -- Significantly extending the performance and reach of high-performance computing and networking interconnects, Gennum Corp. (search for Gennum) has launched the GN2406, which it calls the industry's first quad 10-Gbit/sec clock and data recovery (CDR) device aimed at optical modules, backplanes, line cards, and active copper cable assemblies.

Used to restore and clean digital signals at extremely high data rates, the new quad 10 Gbit/sec CDR is the first to provide a retimed interface for Infiniband quad data rate (QDR), 40-Gigabit Ethernet (XLAUI), and 100-Gigabit Ethernet (CAUI) applications. As a result, module and system designers can design robust, high density, low-cost systems today with Gennum's quad 10-Gbit/sec CDR.

"High-performance computing applications, such as Infiniband QDR, largely rely on low-cost copper interconnects and at 10 Gbits/sec, the impact of signal distortion and noise is significantly more pronounced than at 5 Gbits/sec or lower rates," said Bharat Tailor, director of marketing, networking, storage, and computing, at Gennum. "The GN2406 device solves these issues by integrating a CDR, which effectively re-sets the system jitter budget at both ends of the link resulting in a much more robust system level solution. The end result is the highest level of performance and signal integrity for emerging Inifiniband QDR and 40GbE and 100GbE applications."

The GN2406 is a quad 10 Gbit/sec CDR with output de-emphasis, which is a form of transmit equalization that compensates for the loss of the transmission medium. Using the GN2406, copper cable or backplane trace losses of up to 25 dB can be compensated, thus enabling cable lengths of up to 15 m or backplane link lengths greater than 1 m. Each channel in the GN2406 independently locks to data rates from 9.95 Gbit/sec to 11.3 Gbit/sec. To support legacy data rates, half rate (5Gbit/sec) and quarter rate (2.5 Gbit/sec) operation is also supported. When used with a copper cable, backplane trace, or an optical link, the CDR effectively re-sets the system jitter budget, minimizing the impact of impairments such as jitter and crosstalk on system performance.

The GN2406 CDR also functions without the need for a reference clock, which is important in active cable assembly or optical module applications where clocks are not necessarily available or desirable. With an industry leading power consumption of only 180 mW per lane, the GN2406 is well suited for modules or active cable assemblies utilizing the QSFP or similar form factors.

There is a need for a simple chip-to-chip or chip-to-module interface in 40GbE (XLAUI) and 100GbE (CAUI) applications, with up to 10 lanes of 10 Gbit/sec. The GN2406's ability to integrate four 10-Gbit/sec CDRs into a single package enables this interface, significantly simplifying system design. Additionally, the high sensitivity limiting amplifiers at the input make the new GN2406 suitable for use in 40GbE or 100GbE optical modules.

According to The Linley Group's Jag Bolaria, "The development of the 40GbE and 100GbE standards is well underway, with Infiniband QDR set to ramp through 2009. Gennum has developed a timely solution to address the signal integrity issues these systems will encounter."

In a typical high-speed networking chassis design, the trace lengths from an ASIC on a line card to an ASIC on a switch card can exceed 1 m in length with two connectors in the path. When crosstalk and other impairments are considered, there is a significant burden placed on the ASIC's receiver to compensate for the large losses and tolerate the excessive amount of jitter built up. The use of a high jitter tolerance CDR like the GN2406 as a backplane repeater greatly increases the robustness of the link and provides a simple retimed interface for ASIC communication.

"We are extremely excited to be able to demonstrate real-world 10-Gbit/sec performance of our backplane interconnect technology enabled by Gennum's GN2406," adds Ryan Price, global product manager, Molex Inc., a leading backplane components manufacturer. "As the industry broadens its adoption of multi-gigabit systems, a demonstration of error-free data transmission at 10.3 Gbits/sec over a 1 meter FR408 I-Trac backplane channel provides an important assurance of practicality and robustness of such systems."

Pricing for the GN2406 is $29.00 per unit in quantities of 10,000, and will sample in November with full production slated for April 2009. Evaluation boards for the GN2406 will be available in December, with a full copper cable reference design and backplane reference design available in January 2009.

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