Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www. exa r .c om
PRELIMINARY
XRT73R12
TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT
OCTOBER 2003 REV. P1.0.3
GENERAL DESCRIPTION
The XRT73R12 is a twelve channel fully integrated
Line Interface Unit (LIU) featuring EXAR’s R
3
Technol ogy (Reconfi gurable, Relayless Redunda ncy)
for E3/DS3/STS-1 applications. The LIU incorporates
12 independent Receivers and Transmitters in a
single 420 Lead TBGA package.
Each channel of the XRT73R12 can be
independently configured to operate in 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 XRT73R12’s differential receiver provides high
noise in terference margi n and is able to r eceive data
over 1000 feet of cable or with up to 12 dB of cable
attenuation.
The XRT73R12 provides a Parallel Microprocessor
Interface for programming and control.
The XRT73R12 supports analog, 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.
APPLICATIONS
• E3/DS3 Access Equipment
• DSLAMs
• Digital Cross Connect Systems
• CSU/DSU Equipment
• Routers
• Fiber Optic Terminals
F
IGURE 1. BLOCK DIAGRAM OF THE XRT 73R12
ORDERING INFORMATION
PART NUMBER PACKAGE OPERATING TEMPERATURE RANGE
XRT73R12IB 420 Lead TBGA
-40
°
C to +85
°
C
XRT73R12
Channel 11
Channel 0
Channel n...
Device
Monitor
MTIP_n
MRing_n
DMO_n
Timing
Control
Tx
Pulse
Shaping
HDB3/
B3ZS
Encoder
Tx
Control
MUX
Line
Driver
Remote
LoopBack
HDB3/
B3ZS
Decoder
MUX
AGC/
Equalizer
Peak Detector
LOS
Detector
Slicer
µProcessor Interfac e
Local
LoopBack
Clock & Data
Recovery
Clock
Synthesizer
RD
WR
Addr[7:0]
CS
INT
D[7:0]
TxON
TxClk_n
TxPOS_n
TxNEG_n
RxClk_ n
RxPOS_n
RxNEG/LCV_n
RLOS_n
RLOL_n
RTIP_n
RRing _n
TTIP_n
TRing_n
CLKOUT_n
SFM_en
E3Clk
DS3Clk
STS-Clk/12M
ICT
Pmode
RDY
PCLK
RESET
