Exar Corp. is executing its mission to quickly penetrate the optical telecommunications market by unleashing its second SONET product in a month.
Taking on a short list of entrenched competitors in the field, the Fremont, Calif., company claims its newest offering -- a line-interface unit (LIU) for DS3, E3, and STS-1 transmission -- breaks new ground by fully integrating four transmit/receive channels into a single device.
"We see a lot of people building multiport applications," said Hugh Wright, director of tactical marketing at Exar's communications group. "Say you have an OC-12 box you want to provision among 12 DS3 lines, the components required to do that would take up a lot of area. Card space is becoming a big issue, and a driving factor for people to use this type of product."
The 4-channel transceiver, known as the XRT73L04, is being touted as Exar's "flagship" SONET product, being the first in the market to achieve this level of integration. Previously, devices with up to three channels were available from Exar and Conexant Systems-Exar's only competitor with a multichannel LIU, according to Wright.
By taking an early lead on the integration front, Exar hopes to gain a solid position in the metropolitan area network (MAN), where high-speed WAN data is translated to LAN speeds. Despite its narrow focus on MAN technologies, the company is facing formidable competition in the form of Conexant, TDK Semiconductor, and TranSwitch on the LIU side, as well as Lucent Technologies and PMC-Sierra on the access control side.
Still, the company sees an opportunity to make headway as the need for higher data speeds on the network backbone drive demand for chips supporting DS3 (44.736 Mbit/s), E3 (34.368 Mbit/s), and STS-1 (51.84 Mbit/s) line rates, Wright said.
"We saw we had this strength, and not a lot of competition, so we made the decision to focus on this market space" Wright said. "But the market's growing rapidly, and we expect other companies will do the same."
Exar is putting a lot of stock in its SONET products to expand the telecom portion of its communications business. Telecom-specific products represented a little more than one-third of Exar's total revenue in fiscal 2000, but are expected to increase to 45% next year.
In addition to SONET devices, Exar's telecom products include T1/E1 and T3/E3 interface chips.
The 3.3-V, 4-channel XRT73L04-targeted for multiservice access equipment, digital cross connects, multiplexers, and aggregators-is designed to allow each channel to be independently configured to support DS3, E3, or STS-1 rates. The channels are configurable either via external pins or a microprocessor serial interface-a feature Exar claims is unique to its part, and will be more important as channel densities increase per chip.
Additionally, the chip provides loopback and transmit line monitoring to enable built-in redundancy without external components.
The device contains an integrated equalizer and clock recovery circuit that operates over a wide range of cable lengths. It also integrates a transmit clock duty-cycle correction circuit allowing for a 30%/ 70% clock duty-cycle.
Exar is releasing a functionally equivalent single-port device, aimed at add-drop multiplexers and other applications that require lower cost and higher reliability. The XRT73L00 is a 3.3-V version of an earlier 5-V part.
Samples of the 4- and 1-channel devices are available. The XRT73L04 is housed in a 144-pin TQFP and is priced at $107.40 in 1,000s. The XRT73L00 ships in a 44-pin TQFP and sells for $31.47 in similar quantities.