LXD381 — Evaluation Board for
Octal E1 Applications
Developer Manual
January 2001
As of January 15, 2001, this document replaces the Level One document
Order Number: 249213-001
LXD381 — Evaluation Board for Octal E1 Applications User Guide.
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Contents
General Description ..................................................................................................5
1.1 Features ................................................................................................................5
Evaluation Board Set-Up.........................................................................................7
LXD381 Packing List.............................................................................................7
Equipment Requirements......................................................................................7
Power Connections ...............................................................................................7
Loopback Mode Selection.....................................................................................7
Receive Polarity Selection.....................................................................................8
Output Enable Selection........................................................................................8
Unused Switches...................................................................................................8
Back-End Interface Connection.............................................................................8
Line Interface Connection .....................................................................................9
Line Interface Circuit .............................................................................................9
Board Protection....................................................................................................9
Evaluation Board Schematics.............................................................................10
Figures
LXD381 Evaluation Board.....................................................................................6
S2 Factory Switch Settings ...................................................................................8
Typical Back-End Connector.................................................................................9
Evaluation Board Schematic — Digital I/O..........................................................11
Tables
LOOP0 - 7 Switch Settings....................................................................................7
LXD381 — Evaluation Board for Octal E1 Applications Developer Manual
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Evaluation Board for Octal E1 Applications — LXD381
1.0
General Description
The LXD381 evaluation board is a versatile tool for engineers designing E1 short haul applications
using the LXT381.
The evaluation board operates in Hardware mode only. All device and channel controls are set
using jumper blocks and DIP switches.
The board provides banana jacks for both power and line interface connections. Connectors are
provided for each framer or back-end ASIC interface. An E1 pattern generator/analyzer may be
used to provide external signals for evaluation.
1.1
Features
• Hardware controllable
• ZIF LQFP socket for easy swapping of LXT381
• Banana jacks for power and line interfaces
• 10-pin connectors for framer/ASIC interface
• Socketed termination components for easy experimentation
• Built-in overvoltage protection for line interface and power supply
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Evaluation Board for Octal E1 Applications — LXD381
2.0
Evaluation Board Set-Up
Caution: CMOS devices are static (ESD) sensitive. Take all industry standard precautions when handling the
evaluation board, the LXT381 chip and other sensitive electronic components.
Before proceeding with any evaluation board operations, review the specifications for the LXT381
transceiver.
2.1
LXD381 Packing List
The evaluation board kit contains the following components:
• LXD381 board with LXT381 device installed.
• LXD381 User Guide.
• LXT381 Data Sheet.
2.2
Equipment Requirements
The evaluation board kit includes all the circuit components needed for a successful evaluation.
However, the following lab equipment is required:
• Power Supply (+3.3 VDC).
• Telecom cable or cable simulator (optional).
• E1 pattern generator/analyzer
2.3
2.4
Power Connections
The evaluation board has two power planes (VCC and TVCC) each of which is tied to a separate
red colored banana jack. Connect the +3.3 VDC power supply to both the VCC (B1) and TVCC
(B3) banana jacks. Connect the power supply ground lead to the black banana jack (B2).
Loopback Mode Selection
The LXT381 LOOP signals for channels 0 through 7 are set by the switches in switch block S1. As
Loopback or No Loopback.
Table 1. LOOP0 - 7 Switch Settings
S1 Switch Position
Operation
High
Center
Low
Analog Loopback
No Loopback
Remote Loopback
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LXD381 — Evaluation Board for Octal E1 Applications
2.5
2.6
2.7
Receive Polarity Selection
The polarity of RPOS/RNEG is determined by the CLKE switch in switch block S2. When the
CLKE switch is OFF, RPOS/RNEG are active Low. When set to the ON position, RPOS/RNEG
are active High. Note that the CLKE switch controls the LXT381’s RPOL pin.
Output Enable Selection
The OE switch in switch block S3 controls the operation of the LXT381 output drivers. For normal
operation (driver outputs enabled), set the OE switch to the ON position. Setting the OE switch to
OFF forces the output drivers to the high impedance state.
Unused Switches
Switches 3 and 4, in switch block S2, have no function on the LXD381 and should be set to the
Figure 2. S2 Factory Switch Settings
S2
CLKE
OE
NOTE: OFF position = Low
2.8
Back-End Interface Connection
Eight 10 pin connectors (JP1 - JP8) provide access to the LXT381 digital signals to allow
interfacing the back-end Framer/Mapper or ASIC with an external pattern generator. Figure 3
shows a typical connector (JP1 for channel 0) with the factory installed jumper connecting RCLK
to TCLK. This jumper is normally installed when feeding analog test data from the line interface
(TIP and RING).
8
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Evaluation Board for Octal E1 Applications — LXD381
Figure 3. Typical Back-End Connector
JP1
1
3
2
TCLK 0
GND
4
RCLK 0
TCLK 0
5
7
6
8
TPOS 0
TNEG 0
LOS 0
RPOS 0
RNEG 0
GND
10
9
2.9
Line Interface Connection
Access to the line interface is provided through the green and white banana jacks. The TIP signal is
routed to the white jacks for both transmit and receive directions. The RING signal is routed to the
green jacks for both directions.
2.10
Line Interface Circuit
Two octal transformers are used for channels 0 to 3 and 4 to 7. Transformers, resistors and
capacitors for channels 0 and 4 are socketed for easy swapping (see the LXT381 data sheet for line
interface information). Jumper blocks are provided to configure the receive transformer operation
jumpers configure the transformers for a 1:1 ratio.
2.11
Board Protection
The evaluation board provides line surge protection for both the power supply and the line. Two
transient voltage suppressors (TVS) are included for power supply protection. The E1 line interface
transmitters are protected with Schottky diodes and the receivers are protected by series input
resistors. This protection is sufficient for G.703 Annex B compliance.
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LXD381 — Evaluation Board for Octal E1 Applications
3.0
Evaluation Board Schematics
Figure 4. Evaluation Board Schematic — Data/Control
G N D I O 1
9 1
V C C I O 1
G N D 1
8 9
9 2
V C C I O 0
G N D I O 0
1 8
1 7
V C C 1
9 0
G N D 0
2 0
V C C 0
1 9
10
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