MARCH 25, 2009 -- Allowing the industry to rapidly migrate to the next node in Fibre Channel development (16GFC), Gennum Corp. (search Lightwave for Gennum) has made available its 16GFC SFP+ complete integrated circuit (IC) product, comprised of a clock and data recovery (CDR) (with integrated limiting amplifier) IC, a CDR with integrated equalizer/laser driver IC, and a transimpedance amplifier (TIA). The company is demonstrating the new ICs and a corresponding SFP+ reference design at OFC/NFOEC 2009, March 24-26, Booth #3349.
"By leveraging our proven CDR and TIA technologies, we are first to market with a robust SFP+ IC solution that meets the jitter, cost, and power demands of next-generation 16G Fibre Channel applications," says Bharat Tailor, director of marketing for networking, storage and computing for Gennum. "This comprehensive solution will enable our customers to begin 16G Fiber Channel SFP+ module development today, giving them a critical time-to-market advantage." The company says it has already sampled the devices to several major module suppliers.
The new ICs and reference designs enable development of SFP+ modules using the same form factor and pin-out as previous 8GFC solutions, offering a low-cost, low-power approach that can ease migration to 16GFC data rates. Gennum also offers 8-Gbps and 10-Gbps CDR devices, providing noise immunity needed by networking and storage applications.
The Fibre Channel specification is standardized in the T11 Technical Committee of the International Committee for Information Technology Standards (INCITS), an American National Standards Institute (ANSI)-accredited standards committee. The committee is developing the 16GFC standard, with expected completion later this year. The emerging 16GFC aims to double the throughput of the 8GFC standard and has a defined line rate of 14.025 Gbps. The increased data rate of the emerging standard brings new performance challenges that must be addressed without adding significant cost to overall designs.
Gennum's new offering consists of three separate devices. The GN2015 CDR with integrated limiting amplifier is appropriate for the receive side of the module due to its high sensitivity and high input jitter tolerance. This is important as each 16GFC bit period is only about 70 ps. CDR functionality ensures a clean output signal for routing through the SFP+ connector and into the host system, thereby enabling a direct connection between the SFP+ module and host ASICs.
The GN2016 CDR with integrated equalizer and vertical cavity surface emitting laser (VCSEL) laser driver is targeted at the transmit side of the module as the equalizer is able to compensate for losses on the host board and in the SFP+ module, and the integrated VCSEL driver removes the need for a discrete component. The CDR portion of the GN2016 ensures a clean output for optical transmission.
Both transmit and receive devices operate reference-free and require a 3.3-V power supply, making them suitable for SFP+ modules and backplane/copper interconnect applications. Each device is packaged in a 4x4-mm, RoHS-compliant, 24-pin QFN package.
The GN1065 TIA provides 12 GHz of bandwidth with only 1.2 µA root mean square (rms) noise, allowing for a sensitivity of -19 dBm at 14.025 Gbps. Designed for use with PIN or avalanche photodiodes, the device includes features such as on-chip decoupling and an accurate RSSI circuit to ease implementation within any receiver package.
The power consumption for the 16GFC SFP+ reference design (which incorporates the GN1065, GN2015, and GN2016) leaves room to fit within the SFP+ 1-W limit.
Samples are available now, as well as a complete SFP+ optical module reference design kit, including schematics, layout files, and a design guide. A complete copper cable assembly reference design kit, with or without cables, includes schematics layout files, and a design guide and will be available in June 2009.
For more optical equipment design information, visit the Optical Equipment Design Center