Three-channel transceiver crams in the functions

Exar claims its XRT75L03 is the industry's first three-channel line interface unit (LIU) with an integrated transceiver and jitter attenuator for E3, DS3, and STS-1 applications.

Exar claims its XRT75L03 is the industry's first three-channel line interface unit (LIU) with an integrated transceiver and jitter attenuator for E3, DS3, and STS-1 applications.

The XRT75L03 is the first in a family of new generation multichannel multifunction products from Exar offering innovative capabilities coupled with the inherent low-power requirements afforded by CMOS process technology.

It incorporates three independent receivers, transmitters and jitter attenuators in a single-chip and is compliant with leading industry standards.

The new device is targeted at applications including access equipment, digital crossconnect systems, ATM switches, routers, and fibre-optic terminals.

The XRT75L03 has a fully integrated transmitter, jitter attenuator, receiver equaliser, and clock and data recovery circuit that operate over a wide range of cable lengths.

It incorporates a B3ZS/HDB3 encoder/decoder, transmit drivers with tristate output capability and line monitoring circuitry for redundancy applications.

It also contains 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 XRT75L03 supports E3 (34.368.Mbit/s), DS3 (44.736Mbit/s) and STS-1 (51.84Mbit/s) modes of operation.

The receiver, transmitter, and jitter attenuator 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 phase lock loop (PLL) that allows the input clock duty cycles to range from 30 to 70%.

The XRT75L03 incorporates an advanced crystal-less jitter attenuator that can be programmed to operate 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.

The XRT75L03 can be used as part of a solution for clock smoothing in SONET STS-1 to DS3 mapping.

It provides both serial microprocessor interface as well as hardware mode for configuration and control.

The versatility of the XRT75L03 follows in the footsteps of other Exar devices and provides the essential physical layer elements for any E3, DS3, and STS-1 transmission application.

It provides a seamless interface to Exar's access control devices that include multi-channel DS3/E3 framers (XRT72L5x), multi-channel DS3 ATM UNIs (XRT72L7x), and a M13 multiplexer (XRT72L13).

It can also interface with other commercially available access control devices.

Samples of the XRT75L03 will be available within 90 days.

The XRT75L03 is packaged in a 128-pin TQFP package and operates at the industrial temperature range of -40 to +85C.

An evaluation board is also available to assist with hardware development.

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