Exar Corporation 48720 Kato Road, Fremont CA, 94538 (510) 668-7000 FAX (510) 668-7017 www.exar.com
XRT75L03
THREE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH JITTER ATTENUATOR
JULY 2003
REV. 1.0.4
GENERAL DESCRIPTION
The XRT75L03 is a three-channel fully integrated
Line Interface Unit (LIU) with Jitter Attenuator for E3/
DS3/STS-1
applications.
It
incorporates
3
independent
Receivers,
Transmitters
and
Jitter
Attenuators in a single 128 pin LQFP package.
Each channel of the XRT75L03 can be independently
configured to operate in the data rate, E3 (34.368
MHz), DS3 (44.736 MHz) or STS-1 (51.84 MHz).
Each transmitter can be turned off and tri-stated for
redundancy support or for conserving power.
The XRT75L03’s differential receiver provides high
noise interference margin and is able to receive the
data over 1000 feet of cable or with up to 12 dB of
cable attenuation.
The XRT75L03 incorporates an advanced crystal-
less jitter attenuator per channel that can be selected
either in the transmit or receive path. The jitter
attenuator performance meets the ETSI TBR-24 and
Bellcore GR-499 specifications.
The XRT75L03 provides both Serial Microprocessor
Interface as well as Hardware mode for programming
and control.
The XRT75L03 supports local, remote and digital
loop-backs. The device also has a built-in Pseudo
Random Binary Sequence (PRBS) generator and
detector with the ability to insert and detect single bit
error for diagnostic purposes.
FEATURES
RECEIVER:
On chip Clock and Data Recovery circuit for high
input jitter tolerance
Meets E3/DS3/STS-1 Jitter Tolerance Requirement
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
be either enabled or disabled
On-chip clock synthesizer provides the appropriate
rate clock from a single 12.288 MHz Clock
Provides low jitter output clock
TRANSMITTER:
Compliant with Bellcore GR-499, GR-253 and ANSI
T1.102 Specification for transmit pulse
Tri-state Transmit output capability for redundancy
applications
Each Transmitter can be turned on or off
Transmitters provide Current Output Drive
JITTER ATTENUATOR:
On chip advanced crystal-less Jitter Attenuator for
each channel
Jitter Attenuator can be selected in Receive or
Transmit paths
Meets ETSI TBR 24 Jitter Transfer Requirements
Compliant with jitter transfer template outlined in
ITU G.751, G.752, G.755 and GR-499-CORE,1995
standards
16 or 32 bits selectable FIFO size
Jitter Attenuator can be disabled
CONTROL AND DIAGNOSTICS:
5 wire Serial Microprocessor Interface for control
and configuration
Supports optional internal Transmit driver
monitoring
Hardware Mode for control and configuration
Each channel supports Local, Remote and Digital
Loop-backs
Single 3.3 V ± 5% power supply
5 V Tolerant digital inputs
Available in 128 pin LQFP Package
- 40°C to 85°C Industrial Temperature Range
APPLICATIONS
E3/DS3 Access Equipment
DSLAMs
Digital Cross Connect Systems
CSU/DSU Equipment
Routers
Fiber Optic Terminals