Micro Linear Corp. announced a transceiver chip that replaces three devices per port in the design of fiberoptic Fast Ethernet network interface cards (NICs), repeaters and switches.

The ML6696 is the industry's first chip to lower the cost to design fiberoptic systems by integrating the entire 100BASE-FX physical layer, LED driver and post amplifier (i.e., quantizer). The chip is fully compliant with the 100BASE-FX, IEEE 802.3u standard which transmits data using the 1300nm wavelength of light.

The new chip is also the industry's first to support the emerging 100BASE-SX standard which will accelerate the use of fiber connections by dramatically cutting system costs. The new standard which is being developed by the Telecommunication Industry Association (TIA) can reduce the per port cost of fiber optic systems up to 50 percent by transmitting data using the 820nm wavelength of light. This offers an improvement over the 100BASE-FX standard which is more expensive because of its 1300nm wavelength fiber components.

According to Jason Knickerbocker, Product Marketing Manager, "Our high-integration device is targeted at getting the cost out of fiber-optic Fast Ethernet systems. Our chip attacks the cost problem on two fronts by reducing the cost to implement the 100BASE-FX industry standard, and by providing the enabling technology to implement the emerging low-cost 100BSE-SX standard being developed by the TIA."

According to Allen Dixon, Chair of the Telecommunication Industry Association's (TIA) Fiber Optics LAN Section, "There is a tremendous amount of industry support for the development of the 100BASE-SX Fast Ethernet Short Wavelength interoperability standard which takes advantage of the lower costs associated with using 820 nm optics. Already more than 22 companies are participating in the development of the new standard, operating under TIA's Fiber Optic 2.2 Group.

"By offering network managers a clear, simple and inexpensive fiber-optic up-grade path from 10 Mbps to 100 Mbps, we believe this new standard will greatly facilitate the use of fiber cabling systems to the desktop. We are planning to have an inter-operability demonstration ready to show at Networld + Interop in October."

About 100BASE-SX The proposed 100BASE-SX standard would use light with a wavelength of 820nm to transmit data instead of the 1300nm wavelength currently used in the 100BASE-FX standard. This shorter wavelength will reduce the cost per port of fiberoptic network interface cards (NICs), repeaters and switches by as much as 50 percent. This cost reduction is made possible because the shorter wavelength allows the use of less expensive optical components.

The 100BASE-SX standard also has the benefit of providing a migration path to 100Mbps for the existing installed base of 10Mbps fiber Ethernet (i.e., 10BASE-FL). This is made possible because 100BASE-SX and 10BASE-FL both use the same optical wavelength of 820nm.

About the ML6696 The ML6696 includes 4B/5B encoder/decoder, 125MHz clock recovery/clock generation, LED driver, and post amplifier (i.e., quantizer). The device offers a power down mode that consumes less than 20mA. The chip connects to industry standard controllers via an MII interface.

The integration of the post amplifier required new techniques to reduce noise and isolate the LED driver from the low level sensitive inputs of the post amplifier. These techniques allow 5mV high source impedance signals to have integrity in an environment that is driving 60mA LED currents.

It is difficult to gauge when the -SX standard will be real and in volume production from enough manufacturers. It almost seems that the standard is moving a little too fast and that when this has happened before with other standards things have inexplicably ground to a halt for six months. Nevertheless, that would be just adding cream to the cake for a product that has the capability of selling extremely well to the existing -FX market. A similar gamble for those OEMs in that business is that any new generation design must be capable of moving on to -SX or be entombed if the standard moves too fast for them to react. Using that balance theory a good applications engineer could explain the customer into the chip that will move with him, that he will experience, learn from and understand early on . . .

Nice specifications, nice integration job. The ML6696 is sampling production next month and is priced at $12.25 for 1000-piece lots. It is being fabricated in both a 52-pin PLCC and a 64-pin TQFP. A simplified version of the product, the ML6695, removes the encoder/decoder (often already on controllers) and is priced at $11.75 in 1000-piece lots. It is in the same packages as the 6696 and will be in production in a couple of months.