Exar Corporation 48720 Kato Road, Fremont CA, 94538 (510) 668-7000 FAX (510) 668-7017 www.exar.com
XRT73LC03A
3 CHANNEL DS3/E3/STS-1 LINE INTERFACE UNIT
REV. 1.0.4
GENERAL DESCRIPTION
The XRT73LC03A, 3-Channel, DS3/E3/STS-1 Line
Interface Unit is a low power CMOS version of the
XRT73L03A and consists of three independent line
transmitters and receivers integrated on a single chip
designed for DS3, E3 or SONET STS-1 applications.
Each channel of the XRT73LC03A can be configured
to support the E3 (34.368 Mbps), DS3 (44.736 Mbps)
or the SONET STS-1 (51.84 Mbps) rates. Each
channel can be configured to operate in a mode/data
rate that is independent of the other channels.
In the transmit direction, each channel encodes input
data to either B3ZS (DS3/STS-1) or HDB3 (E3) for-
mat and converts the data into the appropriate pulse
shapes for transmission over coaxial cable via a 1:1
transformer.
In the receive direction, the XRT73LC03A performs
equalization on incoming signals, performs Clock Re-
covery, decodes data from either B3ZS or HDB3 for-
mat, converts the receive data into TTL/CMOS for-
mat, checks for LOS or LOL conditions and detects
and declares the occurrence of Line Code Violations.
FEATURES
Incorporates an improved Timing Recovery circuit
and is pin and functional compatible to XRT73L03A
Meets E3/DS3/STS-1 Jitter Tolerance Require-
ments
Contains a 4-Wire Microprocessor Serial Interface
Full Loop-Back Capability
Transmit and Receive Power Down Modes
Full Redundancy Support
Uses Minimum External components
Single +3.3V Power Supply
Low power CMOS design
5V tolerant I/O
-40°C to +85°C Operating Temperature Range
Available in a 120 pin LQFP package
APPLICATIONS
Digital Cross Connect Systems
CSU/DSU Equipment
Routers
Fiber Optic Terminals
Multiplexers
ATM Switches
FIGURE 1. XRT73LC03A BLOCK DIAGRAM
ENDECDIS
RLOS_(n)
LLB_(n)
RLB_(n)
TAOS_(n)
TPData_(n)
TNData_(n)
TxClk_(n)
TxLEV_(n)
TxOFF_(n)
Channel 2 - (n) = 2
AGC/
Equalizer
Serial
Processor
Interface
Peak
Detector
LOS Detector
Slicer
Clock
Recovery
Data
Recovery
Invert
Loop MUX
HDB3/
B3ZS
Decoder
LOSTHR_(n)
SDI
SDO
SClk
CS
REGR
RTIP_(n)
RRing_(n)
REQEN_(n)
Channel 0 - (n) = 0
Channel 1 - (n) = 1
Notes: 1. (n) = 0, 1, or 2 for respective Channels
2. Serial Processor Interface input pins are shared by the three Channels in HOST Mode and redefined in Hardware Mode.
Device
Monitor
MTIP_(n)
MRing_(n)
DMO_(n)
Transmit
Logic
Duty Cycle Adjust
TTIP_(n)
TRing_(n)
Pulse
Shaping
HDB3/
B3ZS
Encoder
E3_(n)
STS-1/DS3_(n)
Host/(HW)
RLOL_(n) EXClk_(n)
RxOFF
RxClkINV
RxClk_(n)
RPOS_(n)
RNEG_(n)
LCV_(n)
Tx
Control