Gennum Corporation (Gennum) has introduced two new CDR-based reference design kits (RDKs), SFP+ Copper Cable Assembly and SFP+ Optical Module RDKs. The new kits facilitate the fast development of high-performance Fibre Channel and Ethernet modules. The RDKs are based on company’s 8.5 Gb/s and 10 Gb/s clock and data recovery (CDR) technology and deliver SFP+ solutions with the lowest output jitter on the market.
The CDR-based approach to SFP+ designs will reduce system cost and power consumption, enabling these solutions to be used in a variety of high-performance switch applications such as data centers and storage area networks.
Gennum will display its Copper Cable Assembly RDK at the DesignCon conference being held this week at the Santa Clara Convention Center in Santa Clara, California.
The new design kits employ Gennum ClearEdge CDR Technology, which is used to enhance signal quality within the SFP+ module and improve the robustness of the system, reducing the output jitter by 75 percent to less than 0.15UI. CDRs ease the performance requirements that are typically placed on application specific integrated circuits (ASICs) interconnected with the modules. For SFP+ limiting links, a CDR-based approach eliminates the need for external line card components, such as electronic dispersion compensation (EDC) chips, saving up to 1W and $40 per port.
“CDRs allow you to reset the jitter budget within the module and ensure repeatable performance regardless of the type of system the cable or module is plugged into,” said Bharat Tailor, director of marketing, networking, storage and computing, at Gennum. “This enables increased flexibility during system design and eliminates the severe design constraints that can occur as data rates reach 10 Gb/s. The use of CDRs in the module or cable assembly lowers the overall cost and power of the end system since lower cost ASIC solutions and materials can be used and longer trace lengths and link lengths can be implemented, without system performance degradation.”
Copper Cable, Optical SFP+ Solutions Deliver Lowest Output Jitter for Low-power, Lowcost Systems:
Gennum’s SFP+ copper cable assembly solution employs CDR technology in both transmit and receive direction to deliver unprecedented performance with power dissipation substantially below the 1W SFP+ power requirement. Moreover, it solves the interoperability issues that exist in many systems today. As there are many devices and channel impairments within the signal path, variation within these components can reduce the overall system performance beyond an acceptable level. By using CDRs within the copper cable assembly to reset the jitter budget, the performance at the system level will be robust and consistent. Resetting the jitter budget within the cable assembly also enables longer cable lengths or the use of lower cost cable.
Gennum’s CDR-based 850nm SFP+ Optical Module Reference Design Kit is a platform for next generation SFP+ modules. Gennum’s SFP+ optical RDK integrates the CDR functionality into existing components within the module and does not increase the component count. By integrating the CDR with a limiting amplifier in the receive path and a VCSEL driver in the transmit path, Gennum is able to maintain a total module power of less than 1W. Implementing the CDR in the receive path of the module provides more design flexibility to have longer traces to the host, to use lower cost PCB material or to use a lower cost ASIC. By using a CDR in the transmit direction, the transmit eye has a large optical eye mask margin, even with a noisy input to the module. The Optical Module Reference Design Kit also leverages Gennum’s industry leading GN3150 ROSA and GN4150 TOSA solutions, which are used for optical-to-electrical and electrical-to-optical conversion. These components offer best-in-class sensitivity and ensure exceptional crosstalk performance within the module.
Gennum will offer 8.5Gb/s Fibre Channel and 10Gb/s Ethernet versions of both kits. The 8.5 Gb/s and 10Gb/s CDRs are pin compatible, so only one design is required for both applications. The kits include the SFP+ module or assembly, Gerber files, schematics and a design guide.