DS3/Sonet STS-1
Integrated Line Receiver
December 2000-2
XRT7295AT
FEATURES
D
Fully Integrated Receive Interface for DS3 and
STS-1 Rate Signals
D
Integrated Equalization (Optional) and Timing
Recovery
D
Loss-of-Signal and Loss-of-Lock Alarms
D
Variable Input Sensitivity Control
D
5V Power Supply
D
Pin Compatible with XRT7295AE and XRT7295AC
D
Companion Device to T7296 Transmitter
APPLICATIONS
D
Interface to DS-3 Networks
D
Digital Cross-Connect Systems
D
CSU/DSU Equipment
D
PCM Test Equipment
D
Fiber Optic Terminals
GENERAL DESCRIPTION
The XRT7295AT DS3/SONET STS-1 integrated line
receiver is a fully integrated receive interface that
terminates a bipolar DS3 (44.736Mbps) or Sonet STS-1
(51.84Mbps) signal transmitted over coaxial cable. (See
Figure 13).
The device also provides the functions of receive
equalization (optional), automatic-gain control (AGC),
clock-recovery and data retiming, loss-of-signal and
loss-of-frequency-lock detection. The digital system
interface is dual-rail, with received positive and negative
1s appearing as unipolar digital signals on separate
output leads. The on-chip equalizer is designed for cable
distances of 0 to 450ft. from the cross-connect frame to
the device. The receive input has a variable input
sensitivity control, providing three different sensitivity
ORDERING INFORMATION
Operating
Temperature Range
-40°C to + 85°C
settings, to adapt longer cables. High input sensitivity
allows for significant amounts of flat loss within the
system.
Figure 1
shows the block diagram of the device.
The XRT7295AT device is manufactured using linear
CMOS technology. The XRT7295AT is available in a
20-pin plastic SOJ package for surface mounting.
Two versions of the chip are available, one is for either
DS3 or STS-1 operation (the XRT7295AT, this data
sheet), and the other is for E3 operation (the XRT7295AE,
refer to the XRT7295AE data sheet). Both versions are
pin compatible.
For either DS3 or STS-1, an input reference clock at
44.736MHz or 51.84MHz provides the frequency
reference for the device.
Part No.
XRT7295ATIW
Package
20 Lead 300 Mil JEDEC SOJ
Rev. 1.20
E2000
EXAR Corporation, 48720 Kato Road, Fremont, CA 94538
z
(510) 668-7000
z
FAX (510) 668-7017
EXAR [ EXAR CORPORATION ]
