Multilink Technology Corporation, a provider of semiconductor-based solutions that accelerate the deployment of high-speed optical networks, today introduced its next-generation driver; the MTC5527 Limiting Modulator Driver (LMD) for high speed applications up to 13 GB/s. Multilink's Limiting Modulator Drivers are designed to play an important role in Return-to-Zero (RZ) applications and assure consistent operating results. This capability is critical to customers transmitting RZ solution pulses with the performance required for ultra long haul transmission. Unlike linear modulator drivers, a Limiting Modulator Driver has an input limiting device which acts as an input digital switch and thereby makes the output of the driver insensitive to variations of input rise/fall, overshoot, undershoot or noise on rails.

The MTC5527 is a precision multi-chip module for driving Lithium Niobate modulators, and includes an AC coupled single-ended input and output, output amplitude control and eye crossing point control. Compared to earlier Limiting Modulator Drivers, the MTC5527 provides lower power dissipation, lower output jitter, higher input sensitivity, lower rail ripple and faster edge speeds (22 psec), making it an ideal solution for RZ transmission.

David Huff, Multilink Vice President, Product Marketing, said, "This next generation driver marks another sign of Multilink's dedication to the SONET and RZ markets. We're always looking to address the needs of our customers and by enhancing our products through easier integration and higher performance, this will help with their time-to-market needs and increase the return on their capital investment."

The MTC5527 has a small form factor and includes a digital limiting amplifier function to ensure high quality output signal characteristics even with less than ideal input signals. The module's amplitude control feature is specially designed to provide consistent output signal shape and crossing point over the full range of control and provides some of the highest performance in the industry. Working in conjunction with Multilink's multiplexers with integrated clock multiplier unit, demultiplexer with integrated Clock and Data Recovery, Forward Error Correction devices and clock drivers, Multilink is able to provide a complete suite of solutions for high performance, long haul and ultra long haul data transmission.

Multilink Technology Corporation, 300 Atrium Drive, Second Floor, Somerset, NJ 08873-4105. Phone: 732-537-3838; Fax: 732-805-9177

In the transmission space, there are different transmission distances. For the very long reach - the Ultra-long haul transmission distances of about 4,000 kilometers and further - there is an encoding technique used called RZ transmission, return to zero. For shorter distances of about 2,000 km to about 4,000 km the encoding technique is NRZ non-return to zero.

The primary target market for the Multilink Limiting Modulator Driver, the MTC5527, is for RZ transmission, but it is also applicable for NRZ. It uses a clock driver, the MTC5530 that is a half-rate clock driver or the 5531, which is a full-rate clock driver that generates high amplitude sine wave pulses. The clock you use depends on the type of optical fiber you have and its optical characteristics

For the RZ transmission, designers should consider the extra components needed including clock drivers, data drivers, and for complex transmissions there is the possibility of two clock drivers, and large modulators with multiple stages. All this translates into a need for extra board space. The devices that generate these signals require significant power. From the viewpoint of the clock drivers provided, the key performance specification is spectral purity. The spectral purity for the MTC5527 is 7 dBc, which is an outstanding feature. Multilink developed special IP to get very pure signals from the clock drivers. The company also has implemented features in the clock drivers so the support mechanisms needed to get everything working together are built-in to the clock drivers. Features include automatic gain control, phase tuning, both digital and analog phase control, the ability to set the amplitude, and peak detect monitoring.

The MCT5527 is a multichip module (MCM), which is notoriously difficult to make in volume with consistent results. Multilink uses several techniques to get high volume and repeatable results. They use an IC implementation vs. a discreet FET approach to implement the products. The company also designed the modules with special IP so no hand tuning during assembly and no modifications are needed, as compared to the discreet FET approach that needs hand tuning. Multilink also designed the 5527 so it can be automatically assembled, with no human intervention.

The 5527 has some impressive specs like the 22 picosecond rise/fall times and the built-in limiting amp in the first stage. The built-in limiting amp acts as a digital switch. When it is fed a signal by a MUX (as is traditional), it is not dependent on the rise and fall time of the MUX for what the output rise/fall times will do. Neither is it dependent on having a clean signal on the output for how clean the input signal is, in terms of rail quality. The input limiter stage cleans all that up. And then it is followed with broadband amplifiers and the company's special IP with a net result of fast edge speeds and clean rails.

Price and Availability:

MTC5527 Product samples are now available at a cost of $2,500.00 (U.S.) each.
For more information: www.mltc.com