Sep 8 2008
Vitesse Semiconductor Corporation, a leader in advanced ICs for Carrier and Enterprise networks, announced today the VSC7985 and VSC7986, the latest members of Vitesse's industry leading 10 Gbps laser driver family. The VSC7985 and VSC7986 are optimized for use in SFP+ optical transceivers, but provide the flexibility for use in XFP and Xenpak optical modules, and even dense parallel-optic line cards. As a chipset, the new direct-modulated laser diode (DML) drivers are designed to meet the stringent power requirements of 8 Gpbs Fibre Channel as well as 10G Ethernet and SONET/SDH fiber networks. As a single chip, the VSC7985 can be used as a VCSEL driver for short-reach optical applications.
SFP+, a multisource agreement (MSA) module footprint developed through collaboration of the 10G Ethernet and Fibre Channel communities, offers unprecedented densities for next-generation optical system racks. The reduction in transceiver module size and power will allow line cards that support up to 48-ports of 8G Fibre Channel and 10G Ethernet. Module OEMs and system integrators have struggled with meeting the 1W power limit of SFP+ transceivers in long-range fiber applications, especially in laser End-of-Life (EOL) conditions where bias and modulation currents can increase dramatically. The VSC7985 and VSC7986 offer a significant breakthrough in power by saving up to 40% compared to traditional DML drivers, due in part to a unique architecture and low power design. The chipset solution also streamlines a common footprint PCB design to serve both long and short reach optical module applications, thus further reducing the Bill-of-Material (BOM) cost and engineering characterization time.
“This new laser driver family builds on the successful legacy of the VSC7980, VSC7981 and VSC7982 devices, and represents our fourth generation of 10 Gbps laser drivers,” said Angus Lai, product marketing manager at Vitesse. “We designed this new driver chipset solution to solve the key design challenge and serve the ramping 8G Fibre Channel and 10G Ethernet markets which are forecasted to grow at least three-fold over the next three years.”
The VSC7985, a pre-driver which can be used in standalone fashion for short wavelength 8G and 10G SFP+ module designs, offers rich signal integrity features needed in SFP+ applications such as programmable input equalization, output pre-emphasis and de-emphasis. The programmability allows optimization of optical eye margins across several inches of printed circuit board and various VCSEL lasers. The VSC7985 also features a two-wire serial interface or SPI interface to simplify integration in the SFP+ transceiver. The laser driver solution offers optimal jitter and data eye performance.
The companion VSC7986 amplifier is used in TOSA applications and offers DC single-ended coupling direct to a DML laser. The linear, highly-efficient gain amplifier is compact in die size to allow for easy integration in a TO-style package. The DML laser modulation and bias current can be controlled by the VSC7985 thus further reducing power dissipation, eliminating bulky external components and reducing overall board footprint.
These new laser driver devices complement Vitesse’s highly successful receiver chipset products, the VSC7878 Linear TIA and VSC7987 Limiting Post Amplifier which are in production now for the 8G and 10G SFP+ market. The introduction of the VSC7985 and VSC7986 now presents a comprehensive solution for SFP+ and other high density transmit and receive applications. Together, these devices are expected to address more than 90% of the SFP+ market.
The VSC7985 and VSC7986 are sampling now. Electrical and optical evaluation boards are also available to demonstrate the drivers superior performance in SFP+ transceivers and shorten integration development time with lasers.