XRT85L61 Datasheet, PDF (1/16 Pages) Exar Corporation – BITS (BUILDING INTEGRATED TIMING SUPPLY) CLOCK EXTRACTOR

XRT85L61
BITS (BUILDING INTEGRATED TIMING SUPPLY) CLOCK EXTRACTOR
FEBRUARY 2004
REV. 1.0.1
GENERAL DESCRIPTION
The XRT85L61 is an integrated E1, T1, 64KHz
Centralized Clock interface for T1 (1.544Mbps) 100Ω,
E1 (2.048Mbps) 75Ω or 120Ω applications.
The XRT85L61 extracts either 2048kHz or 1544 kHz
clock signals from an E1 (2.048 MHz), T1 (1.544
Mhz) inputs respectively or 64 KHz, 8kHz or 400 Hz
clock signals from the 64kHz reference clock input.
The XRT85L61 includes an on-chip crystal-less jitter
attenuator with 32 bit FIFO that can either be enabled
or disabled.
FEATURES
• Fully integrated single chip solution for E1,T1 or 64
kHz clock synchronization applications.
• Extracts 2048 kHz, 1544 kHz clock and data com-
ponents
• Extracts 64 KHz and 8 kHz, 400 Hz clock informa-
tion
• Line Code Violation alarms
• On-chip digital clock recovery circuit
• Supports 75Ω and 120Ω (E1), 100Ω (T1) applica-
tions.
• Crystal-less digital jitter attenuator with 32-bit FIFO
that can either be enabled or disabled
• Receive loss of signal (RLOS) output
• Meets Telcordia GR-1244-CORE Section 3.4.1 R3-
27 specification
• Meets or exceeds T1 and E1 specifications in ITU
G.703, G.775
• Single +3.3V Supply Operation
• Logic inputs accept either 3.3 V or 5 V levels
• 28 pin TSSOP package
APPLICATIONS
• Universal Clock Synchronization for G.703 Telecom
Formats
• T1/E1 Line Receiver with Clock and Data Recovery
• DSLAM
FIGURE 1. BLOCK DIAGRAM OF THE XRT85L61
RCLKINV
DATA_INV
DATAMUT
JAEN
Reference Inputs
MCLK1
(1.544 MHz for T1)
MCLK2
(2.048 MHz for E1
or 64 kbps)
Line Side
(T1 or E1 or 64 kbps input)
RTIP
RRING
S1
S2
S3
Master Clock
Generator
Rx
Equalizer
Peak Detector
and Slicer
Clock and
Data
Recovery
Mode Select
T1, E1 or 64 kbps
Jitter
Attenuator
LOS
Detector
Clock
Extractor
Line code
and clock
violation
Detector
RPOS
RNEG
RCLK
(64kHz,1544kHz or 2048kHz)
8 kHz (for 64 kbps)
400 Hz (for 64 kbps)
RCLK_LCV/AIS
8 kHz_LCV/BPV
400 Hz_LCV
RLOS
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • [phone] • FAX [phone] • www.exar.com