XRT59L921 查看數據表（PDF） - Exar Corporation
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XRT59L921 Datasheet PDF : 32 Pages
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XRT59L921
TWENTY-ONE CHANNEL E1 LINE INTERFACE UNIT
MARCH 2007
REV. 1.2.1
GENERAL DESCRIPTION
The XRT59L921 is an optimized twenty-one channel,
E1, line interface unit, fabricated using low power
CMOS technology. The device contains twenty-one
independent E1 channels. It is primarily targeted
towards the SDH multiplexers that accommodate
TU12 Tributary Unit Frames. Line cards in these units
multiplex 21 E1 channels into higher SDH rates.
Devices with 21 E1 interfaces such as the
XRT59L921 provide the most efficient method of
implementing 63-channel line cards. Each channel
performs the driver and receiver functions necessary
to convert bipolar signals to logical levels and vice
versa.
The receiver input accepts transformer coupled 1:1
signals, while the transmitter is coupled to the line
using a 1:2 transformer. The same transformer
configuration can be used for both balanced and
unbalanced interfaces. The device offers Loss of
Signal (LOS) detection, that provides an LOS output
indication signal with thresholds and delay that
comply with the ITU G.775 requirements.
FEATURES
• Twenty-One (21) Independent E1 (CEPT) Line
Interface Units (Transmitter, Receiver, and
Recovery)
• Transmit Output Pulses that are Compliant with the
ITU-T G.703 Pulse Template Requirement for
2.048Mbps (E1) Rates
• On-Chip Pulse Shaping for both 75Ω and 120Ω line
drivers
• Detects and Clears LOS (Loss of Signal) Per ITU-T
G.775
• Operates over the Industrial Temperature Range
• Ultra Low power consumption
• 3.3V operation with 5V Tolerant Input
APPLICATIONS
• PDH Multiplexers
• SDH Multiplexers
• Digital Cross-Connect Systems
• DECT (Digital European Cordless Telephone) Base
Stations
• CSU/DSU Equipment
FIGURE 1. BLOCK DIAGRAM OF THE XRT59L921
RTIP_0
RRing_0
Receive
EquRaelcizeeivr e
Equalizer
LOS Detector
LOS Detector
Peak Detector/Slicer
Peak Detector/Slicer
Channels 2 - 20
Channel 1
Channel 0
LOS_0
Receive Output
RIencterivfaecOe utput
Interface
RxPOS_0
RxNEG_0
TTIP_0
TRing_0
TxON
Pulse Shaping Circuit
Pulse Shaping Circuit
Transmit Input Interface
Transmit Input Interface
TxPOS_0
TxCLK_0
TxNEG_0
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www.exar.com
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