™
A CONEXANT BUSINESS
DS3/E3/STS-1 Line lnterface Unit
CX28333/28332/28331
Complete Single-Chip, Multiport Line
Interface Units
The CX28333/28332/28331 line interface units (LIUs)
from Mindspeed Technologies’
™
provide data transceiver
capability over coaxial cable up to 900 feet in an on-
premises environment. The use of programmable pulse
filtering in each independent transmit section simplifies
system implementation by ensuring full compliance with
ANSI T1.102-1993 cross-connect pulse-mask standards.
Independent on-chip band-gap references are included
to enable precise pulse-shape generation. The large
receiver, dynamic range, and minimal requirement for
external components reduce the cost and complexity of
test and monitoring functions in a typical DS3 or E3
front-end design.
>
K E Y F E AT U R E S
>
Receive equalizer requires
no user configuration
>
Programmable pulse
filtering to meet cross-
connect pulse mask
standards (ANSI
T1.102-1993)
>
Meets jitter specifications
of Bellcore GR-499 and
GR-253
>
Large input dynamic range
>
Full-loopback capability
Integrated Alarms and Maintenance
The CX28333, CX28332 and CX28331 feature alarms
for coding violations and loss of signal, a built-in
B3ZS/HDB3 encoder/ decoder, and full-loopback
capability. On-chip facilities for network management
and testing eliminate the need for external circuitry.
The receiver sections for each port of the CX28332 and
CX28333 are completely separate and feature automatic
gain control provided by a variable gain amplifier, clock
recovery phase-locked loop (PLL), receive equalizer
and signal slicer. The sophisticated receive equalizer
recovers the signal attenuated by several different
cable types (such as types 734 and 728) as well as “flat
loss” introduced by many in-service testing and redun-
dant cabling configurations. These line interfaces are
intended to meet all applicable requirements for DS3/E3
and STS-1 data rates. Current ANSI, ETSI, ITU-T and
Bellcore standards are supported.
Many external components have been eliminated, with
the exception of coupling transformers, termination
resistors and supply bypass capacitors. The devices
meet interoperability requirements as defined by the
Bellcore GR-499 and GR-253 jitter specifications.
Each channel has an independent equalizer on the receive
side, requiring no user configuration. Also, each channel
has a programmable transmit pulse shaper that can be
set to ensure the cross-connect pulse mask requirement
is met for transmit cable lengths of up to 450 feet.
Superior input receiver sensitivity allows for a minimum
25 mV receive level.
>
DS3/E3/STS-1 Line lnterface Unit
The CX28333 gives the user new economies of scale in
concentrator applications where three DS3 or STS-1 channels
are mapped into a single STS-3 channel. An optional receive
equalizer setting is provided for test applications using
“square” DS3 as STS-1 test pulses.
The term “DS3” stands for Digital Service at Level 3 of the
digital network hierarchy (also called plesiochronous digital
hierarchy or PDH). The encoded line signal and physical
connection for this service are generally referred to as T3.
Although the transport medium outside customer premises
What is DS3?
DS3 is a dedicated, private-line digital service designed
for point-to-point communications at 43.736 Mbps. It
is suited for organizations requiring very high-capacity
Internet connections that surpass the capabilities of the
more popular DS1 (1.544 Mbps) service. DS3 is also used
by network operators to multiplex 28 of the lower-speed
DS1 connections.
is usually fiber-optic cable, the connection between the
network elements at the customer premises or in network
equipment is generally copper coaxial cable of up to 450
feet in length. However, for wiring using simple patch cables,
repeaters are needed unless the network equipment is
capable of operation over at least two spans of cable (900 feet).
TPOS#
TNEG#
TCLK#
E3MODE#
ENDECDIS
LBO#
TAIS#
LLOOP#
RLOOP#
REFCLK#
PDB#
LOS#
XOE
Encoder
Datamux
AIS
AMIGEN
TXFILT
TXDRV
TLINE#P
TLINE#M
CONTROL
and
LOS
Detect
RPOS#
RNEG#
RCLK#
# = 1, 2, or 3 (CX28333)
# = 1 or 2 (CX28332)
Decoder
Datamux
RXPLL
SLICER
RXEQ
VGA
RLINE#P
RLINE#M
CX28332/CX28333 functional block diagram
CX28333, 28332, 28331
What is E3?
E3 is similar to DS3, but operates at the lower data rate
of 34.368 Mbps. Both transport (which is generally provided
by fiber-optic cable) and the access service are referred
to as E3.
What is STS-1?
STS-1 is at the first level of the synchronous optical
network (SONET). It is a 51.84 Mbps digital transport
or access service which usually transports a single DS3
or up to 28 DS1 services.
CX28333
75
Ω
1:1
DS3
Framer
CX28330
TPOS
TNEG
TCLK
TLINEP
36.5
TX
TLINEM
36.5
75
Ω
1:1
0.01µF
RPOS
RNEG
RCLK
RESET
CHANNEL 1
RLINEP
37.4
RX
BIAS
RLINEM
37.4
75
Ω
1:1
DS3
Framer
CX28330
TPOS
TNEG
TCLK
TLINEP
36.5
TX
TLINEM
36.5
75
Ω
1:1
0.01µF
CHANNEL 1
RPOS
RNEG
RCLK
RESET
RLINEP
37.4
RX
BIAS
RLINEM
37.4
75
Ω
1:1
DS3
Framer
CX28330
TPOS
TNEG
TCLK
TLINEP
36.5
TX
TLINEM
36.5
75
Ω
1:1
0.01µF
RPOS
RNEG
RCLK
RESET
CHANNEL 1
RLINEP
37.4
RX
BIAS
RLINEM
37.4
3.3 V
REFCLK
3
3
3
3
3
3
XOE
PDB
ENDECDIS
LBO
RLOOP
LLOOP
TAIS
LOS
RESET
BIAS
RBIAS
E3MODE
12.1K
µP
Typical connection of CX28333
>
Product Highlights
• Receive equalization for coaxial cable
lengths up to 900 feet
• Can be used as data transceiver over
a maximum of 900 feet of coaxial
cable in an on-premises environment
• Programmable pulse filtering to meet
cross-connect pulse masks (ANSI
T1.102-1993)
• Meets jitter specifications of
Bellcore GR-499 and GR-253
• Large input dynamic range
• Alarms for coding violations and
loss of signal
• Full-loopback capability
• Uses a minimum of external
components
• Compatible with ITU-T G.703
• Channelized line-aggregation units
• Test equipment
• Channel server units
• Multiplexers
Receiver Performance
Sensitivity
• E3: up to 900 feet of type 728 cable
(maximum loss = 12 dB sqrt(f))
• DS3: up to 900 feet of type 728 or
734 cable; up to 450 feet of type
735 cable
• STS-1: up to 1350 feet of type 728
or 734 cable; up to 450 feet of type
735 cable
• Receives signals with minimum
amplitude of 25 mV
Loss of Signal
• 128 ± 1 consecutive zeroes
Transmitter Performance
Intrinsic Jitter
• 0.05 UI maximum, 10 Hz to 100 MHz
Transmit Power
E3:
• Nominal peak voltage of a mark
(pulse) into a test load of 75
Ω
is
± 1.0 V (at the device output)
DS3:
• 22.368 KHz: -1.8 to +5.7 dBm
(75
Ω
± 5% termination)
• 44.736 KHz: at least 20 dB below
the power at 22.368 KHz (at the
first DSX, with 0 to 450 feet of
cable between device and DSX)
• GR-499: pulse amplitude between
± 0.36 V and ± 0.85 V, wideband (DC
to 200 MHz) power between -4.7
to +3.6 dBm (75
Ω
± 5%) for 225
to 450 feet of cable
• STS-1: DC to 207.36 MHz transmit
power between -2.7 and +4.7 dBm
(75
Ω
± 5% termination) for 225 to
450 feet of cable
Data Rates
• DS3: 43.736 Mbps
• E3: 34.368 Mbps
• STS-1: 51.84 Mbps
Cable Type
• 75
Ω
coaxial cable (type 728, type
734, type 735 or similar)
External Components
• 12.1 K
Ω
± 1% resistor for internal-
voltage reference
• 2x 31.6
Ω
transmit termination
resistors (per channel)
• 2x 37.4
Ω
receive termination
resistors plus 0.01µF capacitor
(per channel)
• 1:1 transmit pulse transformer per
channel (Pulse Engineering T3001
or equivalent)
• 1:1 receive pulse transformer per
channel (Pulse Engineering T3001
or equivalent)
Jitter Tolerance
• E3 rate: ITU-T G.823, Section 3, and
ETSI prTBR24 contain frequency
masks for input jitter tolerance
• DS3 rate: ITU-T G.823, Section 2,
and Bellcore GR-499 specify jitter
tolerance frequency masks for
Category I and Category II interfaces
• STS-1 rate: Bellcore GR-253, Section
5.6.2.2, specifies a jitter tolerance.
The STS-1 jitter tolerance differs
from DS3 requirements only for
Category II interfaces
Physical Characteristics
• 80-pin ETQFP package
• Single 3.3 V power supply
• 1,100 mW max. power dissipation
(CX28333)
• -40°C to + 85°C temperature range
• 5 V-tolerant I/O ring
Applications
• Digital cross-connect systems
• Routers
• ATM switches
www.mindspeed.com/salesoffices
General Information:
U.S. and Canada: (800) 854-8099
International: (949) 483-6996
Headquarters – Newport Beach
4000 MacArthur Blvd., East Tower
Newport Beach, CA 92660-3007
Order# 500076A M01-0369
© 2001 Mindspeed Technologies
™
, a Conexant business. All rights reserved. Mindspeed
and the Mindspeed logo are trademarks of Mindspeed Technologies. All other
trademarks are the property of their respective owners. Although Mindspeed
Technologies strives for accuracy in all its publications, this material may contain
errors or omissions and is subject to change without notice.
This material is provided
as is and without any express or implied warranties, including merchantability, fitness
for a particular purpose and non-infringement.
Mindspeed Technologies shall not be
liable for any special, indirect, incidental or consequential damages as a result of its use.
™
A CONEXANT BUSINESS
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