GENERAL DESCRIPTION

The XRT75L04D is a four-channel fully integrated Line Interface Unit (LIU) with Sonet Desynchronizer for E3/DS3/STS-1 applications. It incorporates four independent Receivers, Transmitters and Jitter Attenuators in a single 176 pin QFP package.

Each channel of the XRT75L04D can be configured to operate in E3 (34.368 MHz), DS3 (44.736 MHz) or STS-1 (51.84 MHz) rates that are independent of each other. Each transmitter can be turned off and tristated for redundancy support and for conserving power.

The XRT75L04D’s differential receivers provide high noise interference margin and are able to receive the data over 1000 feet of cable or with up to 12 dB of cable attenuation.

FEATURES

RECEIVER:

• On chip Clock and Data Recovery circuit for high input jitter tolerance.

• Meets the jitter tolerance requirements as specified in ITU-T G.823_1993 for E3 and Telcordia GR-499-CORE for DS3 applications.

• Detects and Clears LOS as per G.775.

• Receiver Monitor mode handles up to 20 dB flat loss with 6 dB cable attenuation.

• On chip B3ZS/HDB3 encoder and decoder that can either be enabled or disabled.

• On-chip clock synthesizer generates the appropriate rate clock from a single frequency XTAL.

• Provides low jitter clock outputs for either DS3,E3 or STS-1 rates.

TRANSMITTER:

• Compliant with Telcordia GR-499, GR-253 and ANSI T1.102 Specification for transmit pulse

• Tri-state Transmit output capability for redundancy applications

• Transmitters can be turned on or off.

JITTER ATTENUATOR:

• On chip advanced crystal-less Jitter Attenuator.

• Jitter Attenuators can be selected in Receive or Transmit paths.

• Compliant with jitter transfer template outlined in ITU G.751, G.752, G.755, GR-253 and GR-499-CORE,1995 standards.

• Meets ETSI TBR 24 Jitter Transfer Requirements.

• 16 ,32 or 128 bits selectable FIFO size.

• Meets the Wander specifications described in T1.105.03b.

• Jitter Attenuators can be disabled.

CONTROL AND DIAGNOSTICS:

• Serial Microprocessor Interface for control and configuration.

• Supports optional internal Transmit Driver Monitoring.

• PRBS error counter register to accumulate errors.

• Supports Local, Remote and Digital Loop-backs.

• Single 3.3 V ± 5% power supply.

• 5 V Tolerant I/O.

• Maximum Power Dissipation 1.8W.

• Available in 176 pin QFP package

• - 40°C to 85°C Industrial Temperature Range.

APPLICATIONS

• E3/DS3 Access Equipment.

• STS1-SPE to DS3 Mapper.

• DSLAMs.

• Digital Cross Connect Systems.

• CSU/DSU Equipment.

• Routers.