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Exar Launches Latest LIUs

Exar's new DS3/E3/STS-1 multi-channel LIU device family and eight-channel E1 short-haul LIU both leverage its R(3) technology

September 22, 2003

7 Min Read

FREMONT, Calif. -- Exar Corporation (NASDAQ:EXAR) , a leading provider of high-performance, mixed-signal silicon solutions for the worldwide communications infrastructure announced the industry's first DS3/E3/STS-1 LIUs leveraging the Company's pioneering R(3) Technology (Reconfigurable, Relayless Redundancy) with an integrated jitter attenuator and SONET desynchronizer. Extending last year's original R(3) Technology offering in its T1/E1/J1 products, Exar has now made this capability available in its DS3/E3/STS-1 devices. Applications include access equipment, digital cross-connect systems, routers, and digital subscriber line access multiplexer (DSLAMs), or any networking equipment located between the high-speed core and the lower-speed access network.

Exar has released five new devices. Two address desynchronization requirements for mapping/demapping between SONET/SDH (synchronous) and DS3/E3 (asynchronous) networking environments: XRT75R03D (three-channel), and XRT75R12D (twelve-channel). Complementing these devices are the XRT75R03 (three-channel) and XRT75R12 (twelve-channel) with on-board jitter attenuator for applications where this capability is needed. Exar also offers a pin compatible device without the jitter attenuator, the XRT73R12. This family of flexible and integrated LIUs allows network OEM equipment providers to take advantage of the market trend to maximize their return from the existing network infrastructure.

"Building on the early adoption and success with customers of R(3) Technology for T1/E1/J1 applications, Exar is now introducing this innovative capability in our higher speed DS3/E3/STS-1 products," said Dr. Roubik Gregorian, executive vice president and chief operating officer. " The new devices demonstrate Exar's continuing commitment to leverage our world-class engineering resources to give customers a wide array of design options and system functionality."

R(3) Technology Overview

Exar's R(3) Technology was first introduced in 2002 as a breakthrough capability delivering key benefits to customers designing interface cards. Devices utilizing the technology are Reconfigurable with integrated clock synthesizer supporting DS3/E3/STS-1 clock rates from a single clock source. This capability enables customers to build one board with a single bill-of-materials, and gives them the agility to quickly respond and reconfigure devices for compressed design cycles. In addition, the series employs Relayless Redundancy eliminating the need for external relays for 1:1 and 1+1 applications by establishing a back-up channel that can be brought on- line in the event of failure.

Desynchronization and Jitter Overview

The process of mapping and subsequent de-mapping of individual DS3 or E3 signals into SONET's Synchronous Payload Envelope (SPE) introduces excessive jitter and timing irregularities. Examples of jitter sources include mapping jitter (caused by bit stuffing) when matching the asynchronous bit rate to a synchronous transport signal; and pointer jitter, the outcome of timing mismatches between two networks that offset the payload and cause pointer movement. As data is transmitted through the network, errors accumulate from these jitter sources and a desynchronizing Phase Locked Loop (PLL) is required to remove the unwanted jitter. Desynchronizing solutions use a combination of a very narrow-bandwidth crystal oscillator based PLL sometimes referred to as a Voltage Control Oscillator (VCXO), and a deep FIFO for each data rate and channel. Exar's solution uses only one highly integrated programmable PLL so each channel can support multi-rate (DS3, E3 or STS-1) operations using the clock from the central PLL and a DSP-based desynchronizer. Here jitter/timing irregularities are removed, and then desynchronized to provide a smooth GR- 253-CORE specification-compliant clock signal. Once this operation is complete the receive signal is suitable for retransmission and returned to the data stream.

Product Details

The XRT75R03/12 incorporate an independent receiver for each channel, transmitter and jitter attenuator, while the XRT75R03D/12D series replaces the jitter attenuator with a desynchronizer. All devices support E3 (34.368.Mbps), DS3 (44.736Mbps) and STS-1 (51.84 Mbps) modes of operation. Each device has a differential receiver, which provides a high noise interference margin capable of receiving data from cables of over 1,000 feet or up to 12dB of cable attenuation. All devices also contain an onboard Pseudo Random Binary Sequence (PRBS) generator and detector with the ability to insert and detect single bit error. This function can be used for diagnostic purposes.

The receiver, transmitter, and jitter attenuator/desynchronizer all meet Bellcore GR-499 CORE requirements. Also, the transmitter meets the GR-253 CORE and ANSI T1.102 specifications and it includes a duty cycle correction PLL that allows the input clock duty cycles to range from 30% to 70%. The XRT75R03/12 incorporate an advanced crystal-less jitter attenuator that can be inserted either in the receive path, transmit path or disabled altogether. The device meets jitter and wander specifications described in the T1.105.03b, and ETSI TBR-24, and is compliant with jitter transfer templates outlined in ITU G.751, G.752 and G.755. All devices provide a serial microprocessor interface as well as hardware mode for configuration and control.

"The XRT75R03/12 and XRT75R03/12D are the latest member of Exar's highly successful DS3/E3/STS-1 product family," said Hugh Wright, director of marketing. "The versatility of the device series follows in the footsteps of other EXAR devices and provides the essential physical layer elements for any DS3, E3 and STS-1 transmission application. In addition, it provides a seamless interface to Exar's access control and data aggregation devices that include multi-channel DS3/E3 framers (XRT72L5x), multi-channel DS3/E3 ATM UNIs (XRT74L7x), and OC-12 mapper (XRT94L43). It will also interface with other commercially available devices.

Prices, Packages and Availability

Samples of the XRT75R03 and XRT75R03D, in 128-pin LQFP packages, are available now, and priced at $51.98 and $58.98 respectively for 1,000 units. Samples of the XRT73R12, XRT75R12 and XRT75R12D, in 420 TBGA packages, are also available now, and priced at $178.38, $205.14 and $235.91 respectively for 1,000 units. All parts are packaged in a 120-pin TQFP package and operate at the industrial temperature range of -40 to 85 degree C. Evaluation boards are also available to assist with hardware development.

In a separate release:

Exar Corporation (NASDAQ:EXAR) , a leading provider of high-performance, mixed-signal silicon solutions for the worldwide communications infrastructure extended its innovative, and industry-proven R(3) Technology to E1 applications with the release of the XRT83SL28. This highly integrated short-haul LIU device is targeted at Multi-Service Provisioning Platforms (MSPPs), access devices, media gateways, routers, and frame relay access devices.

"Utilizing Exar's R(3) Technology for E1-only applications, customers can now leverage its benefits for targeted market opportunities," said Dr. Roubik Gregorian, executive vice president and chief operating officer. "Combined with the Company's T1/E1/J1 eight-channel framer (XRT 84L38) it affords customers significant reductions in board costs, and design complexity."

R(3) Technology Overview

Exar's R(3) Technology (Reconfigurable, Relayless Redundancy), first introduced in 2002 as a breakthrough capability delivering key benefits to customers designing interface cards has now been extended to the E1 environment. The devices are Reconfigurable with integrated termination supporting both 75 and 100 omega line impedances enabling customers to build one board with a single bill-of-materials, and gives them the agility to quickly respond and reconfigure devices for compressed design cycles without the unnecessary stock piling of inventory for all configurations. In addition, the XRT83SL28 employs Relayless Redundancy eliminating the need for external relays for 1:1 and 1+1 applications by establishing a back-up channel that can be brought on-line in the event of failure.

Product Details

The device meets or exceeds popular networking specifications ITU G.703, G.775, ANSI T1.402. and the Bellcore GR-499 core. The device has Exar's industry-proven high-impedance circuits enabling transmitter outputs and receiver inputs to achieve high impedance when there is a power failure, or the LIU is turned off. The device also supports automatic protection switching, local analog, remote and digital loopback modes, has on-chip HDB3 encoder/decoder for each channel, and on-chip digital clock recovery circuit with high input jitter tolerance. Other features include a parallel microprocessor bus supporting both synchronous and asynchronous microprocessor interfaces for Motorola, Intel and MIPS processors.

"The new XRT83SL28 builds on the strong market acceptance of our R(3) technology that is in Exar's T1/E1 products," said Hugh Wright, director of marketing, "allowing our customers to take advantage of this ground breaking capability in their products."

Prices, Packages and Availability

Samples of the XRT83SL28 are available now. It is offered in a 144-pin TQFP and operates at industrial temperature ranges. In 1,000 piece quantities, the XRT83SL28 is $22.49.

Exar Corp.

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