XRT8001
WAN Clock for T1 and E1 Systems
October 2001-1
GENERAL DESCRIPTION
The XRT8001 WAN Clock is a dual-phase-locked loop
chip that generates two very low jitter output clock
signals that can be used for synchronization clocks in
wide area networking systems. The XRT8001 has pre-
programmed multipliers and dividers that are selected
via the serial port. It generates two integer multiples of
8kHz, 56kHz, and 64kHz while locked onto an incom-
ing reference of 1.54MHz (T1), 2.048MHz (E1), 8kHz,
56kHz, or 64kHz
The XRT8001 WAN Clock can be configured to oper-
ate in one of six modes:
1. The Forward/Master Mode
2. The Reverse/Master Mode
3. The “Fractional T1/E1" Reverse/Master Mode
4. The “E1 to T1 - Forward/Master" Mode
5. The “High Speed - Reverse" Mode
6. The “Slave” Mode
FEATURES
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Generates Output Clock Frequencies Ranging
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From 8kHz up to 16.384MHz
Serial Port Control for Optimal Performance
Sync Output: 8kHz or 64kHz
Low Jitter
Cascadable (Master / Slave Modes)
No External Components Needed
Pin Compatible with the XRT8000
Low Power (3.3V or 5V): 40 - 100mW
- 40°C to +85°C Temperature Range
18-Lead PDIP or SOIC Packages
APPLICATIONS
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Dual Phased Locked Loops with
Pre-Programmed Multipliers and Dividers
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Pre-Programmed with Popular Frequency
Conversions for Communications Systems
3.3V or 5V
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T1/E1 Access Equipment (DSU/CSU)
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Frame Relay Access Devices (FRAD)
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Basic Rate and Primary Rate ISDN Equipment
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ISDN Routers
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Terminals
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Remote Access Servers
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T1/E1 Concentrators
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T1/E1 Multiplexers
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T1/E1 Clock Rate Converters
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Internal Timing Generators
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System Synchronizers
V
CC
Reference Clock
8kHz to 16.384 MHz
3
F
IN
XRT8001
CLK1
CLK2
6
Clock Output 1
Clock Output 2
PLL Lock Detect
Sync Out
8kHz or 64kHz
Master/Slave
2
SYNC
13
MSB
8
CS
LOCKDET
SDO
SDI
SCLK
11
µ
C/µ P Serial I/O
µ
Figure 1. System Diagram
ORDERING INFORMATION
Part Number
XRT8001IP
XRT8001ID
Package
18-Lead 300 Mil PDIP
18-Lead 300 Mil JEDEC SOIC
Operating Temperature Range
-40
°
C to +85
°
C
-40
°
C to +85
°
C
Rev. 1.01
EXAR
Corporation, 48720 Kato Road, Fremont, CA 94538
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(510) 668-7000
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FAX (510) 668-7017
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www.exar.com
EXAR [ EXAR CORPORATION ]
