Multilink Technology Corporation (MLTC) , a provider of advanced semiconductor-based solutions that accelerate the deployment of high-speed optical networks, today introduced the MTC5529, the industry's first high performance, very small form factor 12.5 Gb/s Non-Return-to-Zero (NRZ) Modulator Driver (MDR).

Using Multilink's unique Micro-Module technology, this low power, extremely low jitter MDR is in a small form factor (16 x 16 x 1.8 mm) Ball Grid Array (BGA) package. The MTC5529 provides a 75 percent reduction in effective board area utilization compared to standard MDR's currently available in the market. Additionally, by using the MTC5529, customers can substantially reduce the time and cost required for integrating the driver onto their board during the manufacturing process.

"This is the first product using our Micro-Module technology which allows Multilink to incorporate several highly-sophisticated integrated circuits into an easy-to-install BGA package," said Dr. Richard N. Nottenburg, President, Chief Executive Officer and Co-Chairman. "We're moving our leading-edge technologies of previously announced Multilink modules onto a new packaging platform which dramatically reduces power, size, and cost for lithium niobate-based fiber optic transmission."

By combining Multilink's leading-edge product packaging with its benchmark mixed-signal and microwave technologies, the company can offer highly-reliable, superior components that match board characteristics and efficiently manage heat dissipation. These characteristics make it suitable for Multi-Source Agreement (MSA) type module integration. Multilink's Micro-Module technology platform will be used in the future for a wide variety of multi-chip products that enhance transmission system performance while reducing assembly cost and size.

The MTC5529 is a precision multi-chip module for driving NRZ modulators, and includes single-ended or differential input with a single-ended sensitivity of 250 mV. The module provides high quality, single-ended output with amplitude control, precision amplitude monitoring circuitry and eye crossing point control to ensure superior bit error rate performance. The MTC5529 has low power (2.8 W) dissipation, high input sensitivity and low rail ripple which offers customers an ideal solution for metro or long haul applications.

Multilink's product solutions drive system performance to the forefront while minimizing system costs. Multilink has the products, the systems knowledge and the application engineering to partner with its customers and provide optimal product solutions for each application. Multilink is able to provide a complete suite of BGA products and an exceptional physical layer solution for metro and long haul transmission systems, which include Multilink's multiplexers with integrated clock multiplier unit, demultiplexer with integrated clock and data recovery and Super Forward Error Correction devices.

Multilink Technology Corp., 300 Atrium Drive, 2nd Floor, Somerset, NJ 08873-5811. Tel: 732-537-3700; 888-884-5811. Fax: 732-805-9177.

How can you say no to a product that offers you a smaller package, lower price and higher performance than typical products on the market. Multilink has designed this modulator from the ground up with those goals in mind. They reduced the size with a combination of packaging and IC design technology to take what was previously a package size of 1" x 1-1/4" and shrunk that down to a tiny 16 mm x 16 mm ball grid array package. What's really nice about the module from a manufacturing point of view is that it does not need hand assembly. This micro-module uses custom ICs, developed with all parts modeled to work efficiently together and designed to account for the different loading and microwave effects a small package encounters compared to the traditional module driver.

In terms of specifications, the micro-module has a very high sensitivity of 250 mV, is able to drive 7.4 V out, and has a power dissipation of 2.8W. It features crossing point control and amplitude control and offers consistent eye-shape output. The modulator driver controls the eye pattern with a custom-limiting amplifier on the front-end. This amplifier acts as a hard switch and is followed by gang amplifiers, which output a signal with consistent shape and amplitude. This is in contrast to how competitors implement their modulator drivers that use a saturated output amplifier stage to help cleanup the rail quality of the input signals. This design can have problems controlling the output amplitude and maintaining the optimal crossing point.

The MTC5529 will work very well for companies that want to implement greater than 80 km, (also called long reach) telecom applications. What is important for transmit and receive capabilities of signals for these applications is the quality and consistency of the eye opening. And, having fast edge speeds and low jitter maximizes the eye opening. The company states that it has low jitter but I couldn't find the specs on the jitter. Hopefully, they will be available on the final version of the data sheet.

Another factor that affects eye opening is rail ripple, and the lower the better the quality of signal at the eye opening. However, this rail ripple also relates to extinction ratio, which is one of the primary determinants of how far you can optically transmit and receive. The extinction ratio is similar to the signal-to-noise ratio. Extinction ratio is basically a ratio between the amount of light transmitted when the device is on, versus when it's off. Ideally you want to have an infinite extinction ratio, but of course that doesn't happen. To minimize extinction ratio you want a modulated driver interacting with the modulator so it is fully off when it supposed to be off, and that can't really happen either. If you have rails that aren't very clean, especially bottom rails, then it will affect the extinction ratio. The cleaner the bottom rails, the flatter and less likely light will be allowed through the modulator - when it's supposed to be off.

The input sensitivity of 250 mV is impressive and important because this type device is driven by a mux and it is difficult for a mux to keep low power dissipation. Having a high input sensitivity makes this driver useful for a variety of commercial muxes.

And here's a bonus - you may notice that this modulator does not require a heat sink. This is because the heat is dissipated through the bottom of the ball grid array. Another important feature is the amplitude monitoring circuit. Since many applications have different voltage requirements needed to drive them, the MTC5529 supplies an amplitude monitoring circuit to help tune the driver output to the voltages needed for the modulator. It's important to control the output voltage so the modulator turns on and off fully. Typical modulators use a reference pin or output monitor pin that corresponds to the output voltage it is supplying. Typically a control loop feedback monitors the amplitude gain. As long as you have a very accurate reference control pin, the output voltage will be maintained. Multilink put the technology for the control in their customized ICs and have maintained 1% accuracy, compared to 5% or worse accuracy offered by other modulator driver manufacturers.

MTC5529 product samples will be available in February 2002. It is priced at $700 in volume quantities of five thousand.

Datasheet