LevelOne LDB901 User manual

JULY 1997
USER GUIDE
General Description Features
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LDB901 Demo Board
LDB901 Demo Board
for 10BASE-T and AUI applications
Revision 1.1
The LDB901 Demo Board is a complete working platform
that allows system designers to test device performance
and functionality prior to board prototyping. The LDB901
can be used to evaluate the LXT901, LXT907, LXT901A,
LXT907A or LXT908 Universal Ethernet Transceivers
with a few minor modifications to the board.
The LDB901 is designed to interface most standard
controllers to either 10BASE-T cable or 10BASE-2/
10BASE-5 Attachment Unit Interface (AUI) drop cable.
The Demo Board supports standard 10Mbps operation or
full duplex 20Mbps operation. The LDB901 is configured
with a complete set of LED status indicators for major
functions. A single 5V supply is required for operation
with provision for conversion to 3.3V.
This document describes typical Demo Board setup and
operating procedures. Before using the Demo Board,
review the applicable Universal Ethernet Transceiver data
sheet for device functionality and specifications.
• Quick setup for complete system demonstration
• Auto/Manual port (AUI/RJ45) Selection
• Supports standard 10Mbps operation or full duplex
20Mbps operation
• Single 5V Operation
• 4 MAC Controller Capability Modes
• LED indicators for major functions
• Loopback Mode
• Power Down Mode
• Integrated Manchester Encoder/Decoder
• Remote Signaling for LXT901/LXT907 only
•150ΩTermination for LXT901 and LXT901A only
• SQE Disable for LXT907, LXT907A and LXT908
only
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LDB901
 LDB901 Evaluation
R11
J3
GND
VCC JP6 JP4 JP2JP8
AUTOSEL MD0 PAUIL1
MD1TEST NTH UTP
JP5 JP3 JP1JP7
VCC
GND
LNK TX RX COL PLR JAB RCMP RLD RJAB
D1 D7D6D2 D3 D4 D5 D8 D9
J16
U1
U4
C4
C5
CIN
CIP
DIN
DON
DOP
DIP
J9
J10
J13
J11
J12
J14 J15
TPON
TPOP
J5
J7
J8
U5
JP19
P5
J18
GNDA
R1 R2
JP13
JP12
TPIP
TPIN
R9
R8
R10
J17
JP11
J19
LBSEL
RJ45
AUI
GNDA
J2

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EQUIPMENT AND SETUP
Equipment Requirements
The LDB901 Demo Board includes all the components
needed for a successful evaluation. However, the
following additional equipment is recommended:
• NetCom System ET-1000 transceiver test box
•MAU
•NIC
• Category 3 or 5 Unshielded Twisted-Pair (UTP) cable
• Ribbon cable
Test Setup
Figure 1 shows a typical test setup for the basic operation
of the LDB901. The LDB901 is connected to a Network
Interface Card (NIC) on the back-end of the board via
ribbon cable. The TP cable is connected to a MAU via an
RJ45 connector. The MAU plugs into an ET-1000 NetCom
Transceiver Test Box via a 15-pin AUI connector.
Figure 1: Basic Test Setup
Power Supply
The LDB901 Demo Board requires a single 5V power
supply.
Power Supply Option
The LDB901 is designed with a voltage regulator (JP19)
that can be jumpered to supply either 5V or 3.3V to the
LXT901, LXT907, LXT901A, LXT907A or LXT908
devices. If pins 1 and 2 are jumpered, 5V operation is
selected. If pins 2 and 3 are jumpered, the power supply is
converted to 3.3V. Table 1 shows configuration of the
jumper circuitry for the transceiver power supply options.
Signal Attenuation Circuitry
Signal attenuation circuitry (JP20, JP21 and JP22) is
provided for 3.3V operation. During 3.3V operation
these jumpers should be left open to enable signal
attenuation. During 5V operation the jumpers should
be installed to bypass signal attenuation.
UTP
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LDB901
RJ45
MAU
NETCOM
ET-1000
NIC
Ribbon Cable
Table 1: Power Supply Configuration
Jumper Placement
Jumper 5V Operation 3.3V Operation
JP19 Jumper pins 1 & 2 Jumper pins 2 & 3
JP20 Jumper Installed Jumper Open
JP21 Jumper Installed Jumper Open
JP22 Jumper Installed Jumper Open

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LDB901 Equipment and Setup
Configuration Options
The LDB901 Demo Board can be configured for
evaluation of either the LXT901, LXT907, LXT901A,
LXT907A or LXT908 Universal Transceivers with a few
minor modifications.
Magnetics
The LDB901 is supplied from the factory with magnetics
recommended for the applicable transceiver ordered.
Jumpers JP12 and JP13 select the magnetics termination
circuitry. These two jumpers and the magnetics
themselves are the only modifications required to set up the
various Ethernet Transceivers. Configuration for the
various evaluation setups are described below.
LXT901/901A and LXT907/907A
Evaluation
Leave both jumpers open when evaluating the
LXT901, LXT907, LXT901A, or LXT907A. This
configuration requires magnetics with a 1:√2ratio for
the transmit transformer and a 1:1 ratio for the receive
transformer. Table 2 lists some suitable magnetics.
LXT908 Evaluation
Jumper both JP12 and JP13 when evaluating the
LXT908. This configuration requires magnetics with a
1:2 ratio for the transmit transformer and a 1:1 ratio for
the receive transformer. Table 3 lists some suitable
magnetics.
Table 2: LXT901/901A and LXT907/907A
Suitable Magnetics
Manufacturer Part Number
TP Transformers Belfuse A553-0716
Fil-Mag 23Z128SM
Valor PT4069
Table 3: LXT908 Suitable Magnetics
Manufacturer Part Number
TP Transformers Belfuse S553-5999-52
Fil-Mag 23Z118
Valor ST4152

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TEST POINTS
There are 16 Test Points on the LDB901 Demo Board. Table 4 describes these.
Table 4: LDB901 Test Point Descriptions
Label Ref Des Description
GND J1 Ground.
VCCD J2 Digital Power Inputs.
TPON J3 Twisted-Pair Output Negative - Differential output to the TP cable.
TPOP J5 Twisted-Pair Output Positive - Differential output to the TP cable.
TPIP J7 Twisted-Pair Input Positive - Differential input from the TP cable.
TPIN J8 Twisted-Pair Input Negative - Differential input from the TP cable.
CIN J9 AUI Collision Negative - Differential input to the CI circuit.
CIP J10 AUI Collision Positive - Differential input to the CI circuit.
DON J11 AUI Output Negative - Differential output to the AUI transceiver cable.
DOP J12 AUI Output Positive - Differential output to the AUI transceiver cable.
DIN J13 AUI Input Negative - Differential input for the AUI transceiver DI circuit.
DIP J14 AUI Input Positive - Differential input for the AUI transceiver DI circuit.
VCCA J15 Analog Power Inputs.
RJ45 J17 RJ45 Connector.
GNDA J18 Analog Ground.
GNDA J19 Analog Ground.

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LDB901 Jumpers
JUMPERS
There are 17 jumpers on the LDB901 Demo Board. There are nine 3-pin jumpers that can be set High by placing a jumper
across pins 1 and 2 or can be set Low by placing a jumper across pins 2 and 3. There are seven 2-pin jumpers that are either
installed or left open and one 3X2 Header (JP11). Table 5 describes these jumpers and their functions.
Table 5: LDB901 Jumper Descriptions
Ref Des Symbol Function
JP1 UTP
(901)
DSQE
(907/908)
Unshielded Twisted-Pair: Selects media termination for LXT901 only. Set High to select
100Ωtermination for unshielded TP. Set Low to select 150Ωtermination for shielded TP.
Signal Quality Error Disable: Disables SQE for LXT907 and LXT908 only. Set High to
disable SQE. Set Low to enable SQE.
JP2 PAUI Port/AUI Selection: Selects active port. Set High to select AUI port. Set Low to select TP
port. If Automatic Port Selection is enabled, PAUI is ignored.
JP3 NTH Normal Threshold: Set High to select normal TP squelch threshold. Set Low to reduce
normal threshold by 4.5dB.
JP4 MDO Mode Select 0: Selects controller compatibility mode as specified in Table 6.
JP5 MD1 Mode Select 1: Selects controller compatibility mode as specified in Table 6.
JP6 LI Link Test Enable: Set High to enable link integrity test. Set Low, link integrity test is
disabled.
JP7 TEST Test: Connect to VCC.
JP8 AUTOSEL Automatic Port Select: With jumper installed automatic port selection is enabled. (When
automatic port selection is enabled, the LDB901 defaults to the Twisted-Pair port until the
link integrity test fails.)
With the jumper open, manual port selection is enabled and PAUI (JP2) determines the
active port.
JP9 PDN Power Down: This jumper enables Power Down Mode. With the jumper open, Power
Down Mode is disabled.
JP10 FDE Full Duplex: This jumper enables Full Duplex Mode. With the jumper open, the LDB901
operates in normal half duplex mode.
JP11 LBK Loopback: If jumpers are placed in pin 3 and 5, standard loopback function is enabled. Data
transmitted from the back-end is internally looped back through the device and returned to the
back-end.
JP12 - Transformer Termination: JP12 and JP13 selects transformer termination.
Leave both jumpers open when evaluating LXT901 or LXT907. This configuration requires
magnetics with a 1:√2ratio for the transmit transformer and a 1: 1 ratio for the receive trans-
former.
Install both jumpers when evaluating LXT908. This configuration requires magnetics with a
1:2 ratio for the transmit transformer and a 1:1 ratio for the receive transformer.
JP13 -
JP19 - Voltage Regulator: Jumpers installed on pins 1 and 2 selects 5V operation. Jumpers
installed on pins 2 and 3 converts to 3.3V.1
JP20 - Voltage Dividers: When jumpers are left open, attenuates the transmitted signals for 3.3V
operation. When the jumpers are installed, attenuation circuitry is bypassed.
JP21
JP22
1. JP20, JP21 and JP22 must be left open when operating at 3.3V.

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MAC Controller Capability Modes
There are 4 Controller Capability Modes that can be selected by placing a jumper in the appropriate pins on JP4 and JP5.
See Table 6 for Control Mode jumper placement.
Table 6: LDB901 MAC Controller Compatibility Modes
Controller
Mode Controller Manufacturer JP4 (MD1) JP5 (MD0)
Mode 1 For Motorola 68EN360, MPC860, AMD AM7990 or
compatible controllers Pins 2 and 3
(Low)
Pins 2 and 3
(Low)
Mode 2 For Intel 82596 or compatible controllers Pins 2 and 3
(Low)
Pins 1 and 2
(High)
Mode 3 For Fujitsu MB86950, MB86960 or compatible controllers
(Seeq 8005)1Pins 1 and 2
(High)
Pins 2 and 3
(Low)
Mode 4 For National Semiconductor 8390 or compatible controllers
(TI TMS380C26) Pins 1 and 2
(High)
Pins 1 and 2
(High)
1. SEEQ controllers require inverters on CLKI, LBK, RCLK and COL in Mode 3.

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LDB901 LED Indicators
LED INDICATORS
There are 9 status LEDs on the Demo Board. Remote capability is provided only on the LXT901 and LXT907. LEDs D7,
D8 and D9 should be ignored for LXT901A, LXT907A and LXT908. Refer to Table 7 for LED descriptions.
Table 7: LDB901 LED Descriptions
Label Ref Des Description
LNK D1 Link. Indicates Link connection
TX D2 Transmit Data. Indicates data being transmitted
RX D3 Receive Data. Indicates data being received
COL D4 Collision. Indicates collision
PLR D5 Polarity Reverse. Indicates reversed polarity on the TP input
JAB D6 Jabber. Indicates Jabber state
RCMP D7 Remote Signaling Compatibility. Indicates remote signaling compatibility.
Ignore for LXT901A, LXT907A and LXT908
RLD D8 Remote Link Down. Indicates remote link failure.
Ignore for LXT901A, LXT907A and LXT908
RJAB D9 Remote Jabber. Indicates remote device in Jabber Mode.
Ignore for LXT901A, LXT907A and LXT908

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BILL OF MATERIALS
Table 8: LDB901 Bill of Materials
Item Qty Reference Description
1 8 C1, C2, C10, C11, C12, C13,
C14, C15 0.1uF / 50V
2 4 C3, C7, C8, C9 10uF / 6V, Tantalum
3 3 C4, C5, C6 18pF
4 1 D1 LED, Green
5 5 D2, D3, D4, D5, D6 LED, Red
6 3 D7, D8, D9 LED, Yellow
7 9 JP1, JP2, JP3, JP4, JP5, JP6,
JP7, JP8, JP19 Header 3-pin
8 7 JP9, JP10, JP12, JP13, JP20,
JP21, JP22 Header 2-pin
9 1 J16 24-pin DIP Socket
10 1 J17 RJ45
11 15 J1, J2, J3, J5, J7, J8, J9, J10,
J11, J12, J13, J15, J17, J18, J19 Test Point (black)
12 1 P5 Connector DB15 (right angle)
13 2 R1, R2, R12, R13, R14, R15,
R16, R17 50Ω / 1%
14 2 L1, L2 Ferrite Bead
15 2 R3, R5 25Ω / 1%
16 2 R4, R6 21Ω / 1%
17 1 R7 12.4kΩ / 1%
18 3 R8, R9, R10 78Ω / 1%
19 1 R11 330Ω / 1%
20 4 R21, R23, R24, R26 1kΩ
21 2 R22, R25 2.2kΩ
22 1 U1 7405
23 1 U2 TP Transformers
A553-0716-00 for LXT901PC, LXT901APC,
LXT907PC or LXT907APC
TD74-1406Q for LXT908PC
24 1 U4 LXT901PC, LXT901APC, LXT907PC,
LXT907APC or LXT908PC
25 1 Y1 Crystal, 20MHz
26 1 JP11 3X2 Header
27 1 J14 Test Point (red)

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LDB901 Bill of Materials
Figure 2: LDB901 Schematic

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NOTES