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XRT7300
E3/DS3/STS-1 LINE INTERFACE UNIT
FEBRUARY 2002
REV. 1.1.1
FEATURES
GENERAL DESCRIPTION
• Meets E3/DS3/STS-1 Jitter Tolerance Require-
ments
The XRT7300 DS3/E3/STS-1 Line Interface Unit is
designed to be used in DS3, E3 or SONET STS-1 ap-
plications and consists of a line transmitter and re-
ceiver integrated on a single chip.
• Full Loop-Back Capability
• Transmit and Receive Power Down Modes
• Full Redundancy Support
XRT7300 can be configured to support the E3
(34.368 Mbps), DS3 (44.736 Mbps) or the SONET
STS-1 (51.84 Mbps) rates.
• Contains a 4-Wire Microprocessor Serial Interface
• Uses Minimum External components
• Requires Single +5V Power Supply
• -40°C to +85°C Operating Temperature Range
• Available in a 44 pin TQFP package
In the transmit direction, the XRT7300 encodes input
data to either B3ZS (for DS3/STS-1 applications) or
HDB3 (for E3 applications) format and converts the
data into the appropriate pulse shapes for transmis-
sion over coaxial cable via a 1:1 transformer.
APPLICATIONS
In the receive direction the XRT7300 performs equal-
ization on incoming signals, performs Clock Recov-
ery, decodes data from either B3ZS or HDB3 format,
converts the receive data into TTL/CMOS format,
checks for LOS or LOL conditions and detects and
declares the occurrence of line code violations.
• Interfaces to E3, DS3 or SONET STS-1 Networks
• CSU/DSU Equipment
• PCM Test Equipment
• Fiber Optic Terminals
• Multiplexers
The XRT7300 also contains a 4-Wire Microprocessor
Serial Interface for accessing the on-chip Command
registers.
NOTE: This Device is Protected by US Patent # 6,157,270
FIGURE 1. BLOCK DIAGRAM OF THE XRT7300
E3
STS-1/DS3
Host/(HW)
RLOL EXCLK
ICT
RCLK2INV
RTIP
RCLK1
AGC/
Equalizer
Clock
Recovery
Slicer
Invert
RRING
LCV/(RCLK2)
Peak
Detector
REQDIS
Data
Recovery
RPOS
RNEG
HDB3/
B3ZS
Decoder
LOS Detector
LOSTHR
SDI
DECODIS
RLOS
SDO/(LCV)
SClk
Serial
Processor
Interface
LLB
Loop MUX
RLB
CS
ENCODIS
TAOS
REGRESET
TPDATA
TNDATA
TClk
TTIP
HDB3/
B3ZS
Encoder
Transmit
Logic
Pulse
Shaping
Duty Cycle Adjust
TRING
TXLEV
TXOFF
Tx
Control
MTIP
MRING
DMO
Device
Monitor
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www.exar.com