ETC LXT908LC

Data Sheet
MARCH 2000
Revision 1.6
LXT908
Universal 3.3V 10BASE-T and AUI Transceiver
General Description
Features
The LXT908 Universal 10BASE-T and AUI Transceiver is
designed for IEEE 802.3 physical layer applications. It
provides all the active circuitry to interface most standard
802.3 controllers to either the 10BASE-T media or
Attachment Unit Interface (AUI). In addition to standard
10 Mbps Ethernet, the LXT908 also supports full-duplex
operation at 20 Mbps.
Functional Features
LXT908 functions include Manchester encoding/decoding,
receiver squelch and transmit pulse shaping, jabber, link
testing and reversed polarity detection/correction. The
LXT908 can be used to drive either the AUI drop cable or
the 10BASE-T twisted-pair cable with only a simple
isolation transformer. Integrated filters simplify the design
work required for FCC-compliant EMI performance.
Convenience Features
•
•
•
•
•
•
•
•
•
•
•
•
•
The LXT908 is fabricated with an advanced CMOS
process and requires only a single 3.3V power supply.
Applications
Improved Filters - Simplifies FCC Compliance
Integrated Manchester Encoder/Decoder
10BASE-T compliant Transceiver
AUI Transceiver
Supports Standard and Full-Duplex Ethernet
Automatic/Manual AUI/RJ-45 Selection
Automatic Polarity Correction
SQE Disable/Enable function
Power Down Mode with tristated outputs
Four loopback modes
Single 3.3V operation
Available in 64-pin LQFP and 44-pin PLCC package
Commercial (0 to +70°C) and
Extended (-40 to +85°C) temperature range
Diagnostic Features
• 10BASE-T Hub and Switching products
• Four LED Drivers
• AUI/RJ-45 Loopback
• Computer/workstation 10BASE-T LAN adapter boards
LXT908 Block Diagram
AUTOSEL
MD0
MD1
MD2
MODE SELECT LOGIC Controller
Compatibility/
Port Select /
Loopback /
Link test
PAUI
LBK
LI
TCLK
CLKI
WATCHDOG
TIMER
XTAL
OSC
CLKO
TEN
TWISTED PAIR
INTERFACE
Select:
PLS Only
or
PLS / MAU
RC
CMOS
TX
AMP
PULSE SHAPER
AND FILTER
RC
DO
COLLISION/
POLARITY
DETECT
CORRECT
MANCHESTER
ENCODER
TPOPB
TPOPA
TPONA
TPONB
RX
SLICER
TPIP
TPIN
TXD
DROP CABLE
INTERFACE
CD
LEDL
ECL
TX
AMP
SQUELCH / LINK
DETECT
+
DOP
DON
LPBK
RXD
DI
MANCHESTER
DECODER
RCLK
DIP
RX SLICER
DIN
CI
COLLISION LOGIC
COLLISION
RECEIVER
CIP
CIN
COL
LEDR LEDT/PDN
LEDC/FDE
DSQE
NTH JAB
PLR
Refer to www.level1.com for most current information.
)
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
TABLE OF CONTENTS
Pin Assignments and Signal Descriptions .......... 3
Functional Description .......................................... 7
Introduction ......................................................... 7
Controller Compatibility Modes ........................... 7
Transmit Function ............................................... 7
Jabber Control Function ..................................... 8
Receive Function ................................................ 8
SQE Function ..................................................... 8
Polarity Reverse Function................................... 9
Loopback Function ............................................ 9
Collision Detection Function ............................... 9
Link Integrity Test Function .............................. 10
Application Information....................................... 12
External Components ....................................... 12
Layout Requirements........................................ 12
Auto Port Select with External Loopback
Control .............................................................. 12
Full - Duplex Support ........................................ 14
Dual Network Support - 10BASE-T and Token
Ring .................................................................. 15
Manual Port Select & Link Test Function .......... 16
Three Media Application ................................... 18
AUI Encoder/Decoder Only............................... 19
2
Test Specifications ...............................................20
Absolute Maximum Values................................20
Recommended Operating Conditions ...............20
I/O Electrical Characteristics .............................21
AUI Electrical Characteristics............................21
Twisted-Pair Electrical Characteristics ..............22
Switching Characteristics ..................................23
RCLK/Start-of-Frame Timing.............................23
RCLK/End-of-Frame Timing..............................24
Transmit Timing.................................................24
Collision, COL/CI Output and Loopback Timing 25
Mode 1 Timing Diagrams ..................................26
Mode 2 Timing Diagrams ..................................28
Mode 3 Timing Diagrams ..................................30
Mode 4 Timing Diagrams ..................................32
Mode 5 Timing Diagrams ..................................34
Mechanical Specifications...................................36
Revision history ...................................................38
LXT908 LXT908 Pin Assignments and Signal Descriptions
LXT908 PIN ASSIGNMENTS AND SIGNAL DESCRIPTIONS
MD1
MD0
NTH
CIN
CIP
VCC1
DON
DOP
DIN
DIP
PAUI
6
5
4
3
2
1
44
43
42
41
40
Figure 1: LXT908 Pin Assignments
39
TPIN
38
TPIP
37
DSQE
36
TPONB
35
TPONA
34
VCC2
33
GND2
32
TPOPA
CLKI
12 (Date Code)
13 (Trace Code)
(Part#) LXT908PC/PE
14
(Lot#) XXXXXX
15
31
TPOPB
COL
16
30
PLR
AUTOSEL
17
29
n/c
25
26
27
28
MD2
RXD
CD
RCLK
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
n/c
n/c
TPIN
TPIP
n/c
DSQE
TPONB
TPONA
VCC2
GND2
TPOPA
TPOPB
PLR
n/c
n/c
n/c
24
CLKO
RBIAS
TEN
XXXX XXXX
23
TXD
GND1
11
22
TCLK
21
10
LEDC/FDE
LBK
TEST
20
9
19
JAB
18
8
LEDR
7
LI
LEDT/PDN
LEDL
n/c
(Date Code) XXXX XXXX
(Trace Code)
(Part#)
LXT908LC/LE
(Lot#)
XXXXXX
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
n/c
RCLK
CD
RXD
MD2
n/c
RBIAS
n/c
GNDA
GND1
LBK
LEDC/FDE
LEDL
LEDT/PDN
LEDR
n/c
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
n/c
n/c
LI
n/c
JAB
TEST
TCLK
TXD
TEN
CLKO
CLKI
COL
AUTOSEL
n/c
n/c
n/c
n/c
n/c
PAUI
DIP
DIN
n/c
DOP
DON
VCCA
VCC1
CIP
CIN
NTH
MD0
MD1
n/c
3
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Table 1:
LXT908 Signal Descriptions
Pin#
4
Symbol
I/O
10
56
VCC1
VCC2
–
–
Power 1 and 2. Connect to positive power supply terminal (+3.3V DC).
–
9
VCCA
–
Analog Supply. (+3.3V)
2
3
11
12
CIP
CIN
I
I
AUI Collision Pair. Differential input pair connected to the AUI
transceiver CI circuit. The input is collision signaling or SQE.
4
13
NTH
I
Normal Threshold. When NTH is High, the normal TP squelch threshold is
in effect. When NTH is Low, the normal TP squelch threshold is reduced by
4.5 dB.
5
6
25
14
15
44
MD0
MD1
MD2
I
I
I
Mode Select 0 (MD0), Mode Select 1 (MD1) and Mode Select 2 (MD2).
Mode select pins determine the controller compatibility mode as specified in
Table 2.
7, 29
1, 2, 6
16, 17
18, 20
30, 31
32, 33
41, 43
48, 49,
50, 51,
60, 63,
64
N/C
–
No Connect. These pins may be left unconnected or tied to ground.
8
19
LI
I
Link Test Enable. Controls Link Integrity Test; enabled when High,
disabled when Low.
9
21
JAB
O
Jabber Indicator. Output goes High to indicate Jabber state.
10
22
TEST
I
Test. This pin must be tied High.
11
23
TCLK
O
Transmit Clock. A 10 MHz clock output. This clock signal should be
directly connected to the transmit clock input of the controller. TCLK goes
to high impedance (tri-state) when LEDT/PDN is pulled Low externally.
12
24
TXD
I
Transmit Data. Input signal containing NRZ data to be transmitted on the
network. TXD is connected directly to the transmit data output of the
controller.
13
25
TEN
I
Transmit Enable. Enables data transmission and starts the Watch-Dog
Timer. Synchronous to TCLK (see Test Specifications for details).
14
15
26
27
CLKO
CLKI
O
I
Crystal Oscillator. A 20 MHz crystal must be connected across these pins,
or a 20 MHz clock applied at CLKI with CLKO left open.
16
28
COL
O
Collision Detect. Output driving the collision detect input of the controller.
COL goes to high impedance (tri-state) when LEDT/PDN is pulled Low
externally.
PLCC
LQFP
1
34
Description
LXT908 LXT908 Pin Assignments and Signal Descriptions
Table 1:
LXT908 Signal Descriptions – continued
Pin#
Symbol
I/O
29
AUTOSEL
I
Automatic Port Select. When High, automatic port selection is enabled
(the LXT908 defaults to the AUI port only if TP link integrity = Fail).
When Low, manual port selection is enabled (the PAUI pin determines the
active port).
18
34
LEDR
O
Receive LED. Open drain driver for the receive indicator LED. Output is
pulled Low during receive, except when data is being looped back to DIN/
DIP from a remote transceiver (external MAU). LED “On” time (Low
output) is extended by approximately 100 ms.
19
35
LEDT/
PDN
O
I
Transmit LED (LEDT)/Power Down (PDN). Open drain driver for the
transmit indicator LED. Output is pulled Low during transmit. Do not
allow this pin to float. If unused, tie High. LED “On” time (Low output)
is extended by approximately 100 ms. If externally tied Low, the LXT908
goes to power down state. In power down state, TCLK, COL, RXD, CD,
and RCLK (pins 11, 16, 26, 27, and 28, respectively) are tri-stated.
20
36
LEDL
O
I
Link LED. Open drain driver for link integrity indicator LED. Output is
pulled Low during link test pass. If externally tied Low, internal circuitry is
forced to “Link Pass” state and the LXT908 will continue to transmit link
test pulses.
21
37
LEDC/
FDE
O
I
Collision LED (LEDC)/Full Duplex Enable (FDE). Open drain driver for
the collision indicator LED pulls Low during collision. LED “On” time
(Low output) is extended by approximately 100 ms. If externally tied Low,
the LXT908 disables the internal TP loopback and collision detection circuits to allow full-duplex operation or external TP loopback.
22
38
LBK
I
Loopback. Enables internal loopback mode. Refer to Functional
Description and Test Specifications for details.
23
33
39
55
GND1
GND2
–
–
Ground Returns 1 and 2. Connect to negative power supply terminal
(ground).
–
40
GNDA
–
Analog Ground. Ground for analog plane.
24
42
RBIAS
I
Bias Control. A 12.4 kΩ 1% resistor to ground at this pin controls operating
circuit bias.
26
45
RXD
O
Receive Data. Output signal connected directly to the receive data input of
the controller. RXD goes to high impedance (tri-state) when LEDT/PDN is
pulled Low externally.
27
46
CD
O
Carrier Detect. An output to notify the controller of activity on the
network. CD goes to high impedance (tri-state) when LEDT/PDN is pulled
Low externally.
28
47
RCLK
O
Receive Clock. A recovered 10 MHz clock that is synchronous to the
received data and connected to the controller receive clock input. RCLK
goes to high impedance (tri-state) when LEDT/PDN is pulled Low
externally.
30
52
PLR
O
Polarity Reverse. Output goes High to indicate reversed polarity at the TP
input.
PLCC
LQFP
17
Description
5
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Table 1:
LXT908 Signal Descriptions – continued
Pin#
6
Symbol
I/O
Description
54
57
TPOPA
TPONA
O
O
31
36
53
58
TPOPB
TPONB
O
O
Twisted-Pair Transmit Pairs A & B. Two differential driver pair outputs
(A and B) to the twisted-pair cable. The outputs are pre-equalized. Each pair
must be shorted together with an 11.5 Ω 1% resistor to match an impedance
of 100Ω.
37
59
DSQE
I
Disable SQE. When DSQE is High, the SQE function is disabled. When
DSQE is Low, the SQE function is enabled. SQE must be disabled for
normal operation in Hub/Switch applications.
38
39
61
62
TPIP
TPIN
I
I
Twisted-Pair Receive Pair. A differential input pair from the TP cable.
Receive filter is integrated on chip. No external filters are required.
40
3
PAUI
I
Port/AUI Select. In Manual Port Select mode (AUTOSEL Low), PAUI
selects the active port. When PAUI is High, the AUI port is selected. When
PAUI is Low, the TP port is selected. In Auto Port Select mode, PAUI must
be tied to ground.
41
42
4
5
DIP
DIN
I
I
AUI Receive Pair. Differential input pair from the AUI transceiver DI
circuit. The input is Manchester encoded.
43
44
7
8
DOP
DON
O
O
AUI Transmit Pair. A differential output driver pair for the AUI transceiver
cable. The output is Manchester encoded.
PLCC
LQFP
32
35
LXT908 LXT908 Functional Description
LXT908
FUNCTIONAL DESCRIPTION
Introduction
Controller Compatibility Modes
The LXT908 Universal 10BASE-T and AUI Transceiver
performs the physical layer signaling (PLS) and Media
Attachment Unit (MAU) functions as defined by the IEEE
802.3 specification. It functions as an AUI (PLS-Only
device) for use with 10BASE-2 or 10BASE-5 coaxial cable
networks, or as an Integrated PLS/MAU for use with
10BASE-T twisted-pair (TP) networks. In addition to
standard 10 Mbps operation, the LXT908 also supports
full-duplex 20 Mbps operation.
The LXT908 is compatible with most industry-standard
controllers including devices produced by Advanced Micro
Devices (AMD), Motorola, Intel, Fujitsu, National
Semiconductor, Seeq, and Texas Instruments, as well as
custom controllers. Five different control signal timing
and polarity schemes (Modes 1 through 5) are required to
achieve this compatibility. Mode select pins (MD2:0)
determine Controller compatibility modes as listed in
Table 2. Refer to Test Specifications for a complete set of
timing diagrams for each mode.
The LXT908 interfaces a back-end controller to either an
AUI drop cable or a TP cable. The controller interface
includes transmit and receive clock and NRZ data
channels, as well as mode control logic and signaling. The
AUI interface comprises three circuits: Data Output (DO),
Data Input (DI), and Collision (CI). The TP interface
comprises two circuits: Twisted-Pair Input (TPI) and
Twisted-Pair Output (TPO). In addition to the three basic
interfaces, the LXT908 contains an internal crystal
oscillator and four LED drivers for visual status reporting.
Functions are defined from the back end controller side of
the interface. The LXT908 Transmit function refers to data
transmitted by the back end to the AUI cable (PLS-Only
mode) or to the TP network (Integrated PLS/MAU mode).
The LXT908 Receive function refers to data received by
the back end from the AUI cable (PLS-Only) or from the
TP network (Integrated PLS/MAU mode).
In the
integrated PLS/MAU mode, the LXT908 performs all
required MAU functions defined by the IEEE 802.3
10BASE–T specification such as collision detection, link
integrity testing, signal quality error messaging, jabber
control, and loopback. In the PLS-Only mode, the LXT908
receives incoming signals from the AUI DI circuit with
±18 ns of jitter and drives the AUI DO circuit.
Transmit Function
The LXT908 receives NRZ data from the controller at the
TXD input as shown in the block diagram on the first page
of this Data Sheet, and passes it through a Manchester
encoder. The encoded data is then transferred to either the
AUI cable (the DO circuit) or the TP network (the TPO
circuit). The advanced integrated pulse shaping and
filtering network produces the output signal on TPON and
TPOP, shown in Figure 2. The TPO output is pre-distorted
and pre-filtered to meet the 10BASE-T jitter template. An
internal continuous resistor-capacitor filter is used to
remove any high-frequency clocking noise from the pulse
shaping circuitry. Integrated filters simplify the design
work required for FCC-compliant EMI performance.
During idle periods, the LXT908 transmits link integrity
test pulses on the TPO circuit (if LI is enabled and
integrated PLS/ MAU mode is selected). External resistors
control the termination impedance.
Figure 2: LXT908 TPO Output Waveform
4V
2V
0V
-2V
-4V
Table 2:
Controller Compatibility Mode Options
Controller Mode
MD2
MD1
MD0
Mode 1 - For AMD AM7990, Motorola 68EN360, MPC860 or compatible controllers
Low
Low
Low
Mode 2 - For Intel 82596 or compatible controllers
Low
Low
High
Mode 3 - For Fujitsu MB86950, MB86960 or compatible controllers (Seeq 8005)1
Low
High
Low
Mode 4 - For National Semiconductor 8390 or compatible controllers (TI TMS380C26)
Low
High
High
Mode 5 - For custom controllers (Mode 3 with TCLK, RCLK and COL inverted)
High
High
Low
1. SEEQ controllers require inverters on CLKI, LBK, RCLK, and COL in Mode 3; or on CLKI, LBK, and TCLK in Mode 5.
7
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Jabber Control Function
Figure 3 is a state diagram of the LXT908 Jabber control
function.
The LXT908 on-chip Watch-Dog Timer
prevents the DTE from locking into a continuous transmit
mode. When a transmission exceeds the time limit, the
Watch-Dog Timer disables the transmit and loopback
functions, and activates the JAB pin. Once the LXT908 is
in the jabber state, the TXD circuit must remain idle for a
period of 0.25 to 0.75 seconds before it will exit the jabber
state.
Figure 3: Jabber Control Function
Power On
No Output
DO=Active
Nonjabber Output
Start_XMIT_MAX_Timer
DO=Active ∗
XMIT_Max_Timer_Done
DO=Idle
data streams above the squelch level and with proper
timing. If the differential signal at the TPI or the DI circuit
inputs falls below 75% of the threshold level (unsquelched)
for 8 bit times (typical), the LXT908 receive function
enters the idle state. If the polarity of the TPI circuit is
reversed, LXT908 detects the polarity reverse and reports
it via the PLR output. The LXT908 automatically corrects
reversed polarity.
SQE Function
In the integrated PLS/MAU mode, the LXT908 supports
the signal quality error (SQE) function as shown in
Figure 3, although the SQE function can be disabled. After
every successful transmission on the 10BASE-T network
when SQE is enabled, the LXT908 transmits the SQE
signal for 10BT ± 5BT over the internal CI circuit, which
is indicated on the COL pin of the device. SQE must be
disabled for normal operation in hub and switch
applications. In TP applications, the SQE function is
disabled when DSQE is set High, and enabled when DSQE
is Low. When using the 10BASE-2 port of the LXT908, the
SQE function is determined by the external MAU attached.
Figure 4: SQE Function
Jab
Power On
XMIT=Disable
LPBK=Disable
CI=SQE
Output Idle
DO=Idle
DO=Active
Unjab Wait
Start_Unjab_Timer
XMIT=Disable
LPBK=Disable
CI=SQE
Output Detected
DO=Idle
SQE Wait Test
Start_SQE_Test__Wait_Timer
Unjab_ Timer_Done
DO=Active ∗
Unjab_Timer_Not_Done
Receive Function
The LXT908 receive function acquires timing and data
from the TP network (the TPI circuit) or from the AUI (the
DI circuit). Valid received signals are passed through the
on-chip filters and Manchester decoder then output as
decoded NRZ data and recovered clock on the RXD and
RCLK pins, respectively.
XMIT=Disable
SQE_Test__Wait_Timer_Done ∗
XMIT=Enable
SQE Test
Start_SQE_Test_Timer
CI=SQE
SQE_Test_Timer_Done
An internal RC filter and an intelligent squelch function
discriminate noise from link test pulses and valid data
streams. The receive function is activated only by valid
8
LXT908 LXT908 Functional Description
Polarity Reverse Function
Collision Detection Function
The LXT908 polarity reverse function uses both link pulses
and end-of-frame data to determine polarity of the received
signal. A reversed polarity condition is detected when
eight opposite receive link pulses are detected without
receipt of a link pulse of the expected polarity. Reversed
polarity is also detected if four frames are received with a
reversed start-of-idle. Whenever a correct polarity frame
or a correct link pulse is received, these two counters are
reset to zero. If the LXT908 enters the link fail state and no
valid data or link pulses are received within 96 to 128 ms,
the polarity is reset to the default non-flipped condition. If
Link Integrity Testing is disabled, polarity detection is
based only on received data. Polarity correction is always
enabled.
The collision detection function operates on the twisted
pair side of the interface. For standard (half-duplex)
10BASE-T operation, a collision is defined as the
simultaneous presence of valid signals on both the TPI
circuit and the TPO circuit. The LXT908 reports collisions
to the back-end via the COL pin. If the TPI circuit becomes
active while there is activity on the TPO circuit, the TPI
data is passed to the back-end over the RXD circuit,
disabling normal loopback. Figure 5 is a state diagram of
the LXT908 collision detection function. Refer to Test
Specifications for collision detection and COL/CI output
timing NOTE: For full-duplex operation, the collision
detection circuitry must be disabled.
Figure 5: Collision Detection Function
Loopback Function
The LXT908 provides the normal loopback function
specified by the 10BASE-T standard for the twisted-pair
port. The loopback function operates in conjunction with
the transmit function. Data transmitted by the back-end is
internally looped back within the LXT908 from the TXD
pin through the Manchester encoder/decoder to the RXD
pin and returned to the back-end. This “normal” loopback
function is disabled when a data collision occurs, clearing
the RXD circuit for the TPI data. Normal loopback is also
disabled during link fail and jabber states.
The LXT908 also provides three additional loopback
functions. An external loopback mode, useful for systemlevel testing, is controlled by pin 21 (LEDC). When LEDC
is tied Low, the LXT908 disables the collision detection
and internal loopback circuits, to allow external loopback
or full-duplex operation.
“Normal” TP loopback is controlled by pin 22 (LBK).
When the TP port is selected and LBK is High, TP
loopback is “forced”, overriding collisions on the TP
circuit. When LBK is Low, normal loopback is in effect.
AUI loopback is also controlled by the LBK pin. When the
AUI port is selected and LBK is High, data transmitted by
the back-end is internally looped back from the TXD pin
through the Manchester encoder/decoder to the RXD pin.
When LBK is Low, no AUI loopback occurs.
A
DO=Active ∗
TPI=Idle ∗
XMIT=Enable
Power On
Idle
TPI=Active
Output
Input
TPO=DO
DI=DO
DI=TPI
DO=Active ∗
TPI=Active ∗
XMIT=Enable
DO=Active ∗
TPI=Active ∗
XMIT=Enable
Collision
A
DO=Idle +
XMIT=Disable
TPO=DO
DI=TPI
CI=SQE
DO=Active ∗
TPI=Idle
A
TPI=Idle
DO=Idle
9
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Link Pulse Transmission
The LXT908 transmits standard link pulses which meet the
10BASE-T specifications. Figure 6 shows the link integrity
pulse timing.
Figure 6: Transmitted Link Integrity Pulse Timing
10-20 ms
10
10-20 ms
10-20 ms
10-20 ms
10-20 ms
10-20 ms
10-20 ms
10-20 ms
10-20 ms
LXT908 LXT908 Functional Description
Link Integrity Test Function
Figure 7 is a state diagram of the LXT908 Link Integrity
test function. The link integrity test is used to determine
the status of the receive side twisted-pair cable. Link
integrity testing is enabled when pin 8 (LI) is tied High.
When enabled, the receiver recognizes link integrity pulses
which are transmitted in the absence of receive traffic.
If no serial data stream or link integrity pulses are detected
within 50 - 150 ms, the chip enters a link fail state and
disables the transmit and normal loopback functions. The
LXT908 ignores any link integrity pulse with interval less
than 2 - 7 ms. The LXT908 will remain in the link fail state
until it detects either a serial data packet or two or more link
integrity pulses.
Figure 7: Link Integrity Test Function
Power On
Idle Test
Start_Link_Loss_Timer
Start_Link_Test_Min_Timer
Link_Loss_Timer_Done
∗ TPI=Idle
∗ Link_Test_Rcvd=False
TPI=Active +
(Link_Test_Rcvd=True
∗ Link_Test_Min_Timer_Done)
Link Test Fail Reset
Link Test Fail Wait
Link_Count=0
XMIT=Disable
RCVR=Disable
LPBK=Disable
TPI=Active
Link_Test_Rcvd=False
∗ TPI=Idle
XMIT=Disable
RCVR=Disable
LPBK=Disable
Link_Count=Link_Count + 1
TPI=Active
Link_Test_Rcvd=Idle
∗ TPI=Idle
Link Test Fail
Start_Link_Test_Min_Timer
Start_Link_Test_Max_Timer
XMIT=Disable
RCVR=Disable
LPBK=Disable
TPI=Active +
Link_Count=LC_Max
Link_Test_Min_Timer_Done
∗ Link_Test_Rcvd=True
Link Test Fail Extended
XMIT=Disable
RCVR=Disable
LPBK=Disable
TPI=Idle ∗
DO=Idle
(TPI=Idle ∗ Link_Test_Max_Timer_Done) +
(Link_Test_Min_Timer_Not_Done
∗ Link_Test_Rcvd=True)
11
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
APPLICATION INFORMATION
Figures 8 through 14 show some typical LXT908
applications.
Layout Requirements
External Components
Auto Port Select with External
Loopback Control
Crystal Information
Suitable crystals are available from various manufacturers.
Table 3 lists some suitable crystals based on limited
evaluation. Designers should test and validate all crystals
before using them in production.
Table 3:
Suitable Crystals
Manufacturer
Part Number
MTRON
MP-1
MP-2
Magnetic Information
The TP interface requires a 1:1 ratio for the receive
transformer and a 1:2 ratio for the transmit transformer.
The AUI interface requires a 1:1 ratio for the data-in, dataout, and collision-pair transformers. A cross-reference list
of suitable magnetics and part numbers is available in
Application Note 73, Magnetic Manufacturers, which can
be found on the Level One web site (www.level1.com).
Designers should test and validate all magnetics before
committing to a specific component.
Figure 8 is a typical LXT908 application. The diagram is
arranged to group similar pins together; it does not
represent the actual LXT908 pin-out. The controller
interface pins (TXD, RXD, TEN, TCLK, RCLK, CD,
COL, and LBK) are shown at the top left.
Programmable option pins are grouped center left. The
PAUI pin is tied Low and all other option pins are tied
High. This setup selects the following options:
• Automatic Port Selection
(PAUI Low and AUTOSEL High)
• Normal Receive Threshold (NTH High)
• Mode 4, compatible with National
controllers (MD2:0 = Low, High, High)
NS8390
• SQE Disabled (DSQE High)
• Link Testing Enabled (LI High)
Status outputs are grouped at lower left. Line status outputs
drive LED indicators and the Jabber and Polarity status
indicators are available as required.
Power and ground pins are shown at the bottom of the
diagram. A single power supply is used for both VCC1 and
VCC2 with a decoupling capacitor installed between the
power and ground busses.
An additional power and ground pin (VCCA and GNDA)
is supported in designs using the 64-pin LQFP package. A
single power supply is used for all three power and ground
pins (VCC1, VCC2, VCCA) and (GND1, GND2, GNDA).
Install a decoupling capacitor between each power and
ground buss.
The TP and AUI interfaces are shown at upper and lower
right, respectively. Impedance matching resistors for 100
UTP are installed in each I/O pair but no external filters are
required.
12
LXT908 Application Information
Figure 8: LAN Adapter Board - Auto Port Select with External Loopback Control
TXE
TXC
NS8390 BACK-END
CONTROLLER
INTERFACE
RXC
RXD
CRS
COL
LOOPBACK
ENABLE
LBK
CLKI
CLKO
RJ45
TXD
1
TPIN
TEN
TCLK
RCLK
RXD
CD
1 : 1 16
6
100 Ω
5
14
3
TPIP
4
COL
LBK
TPONB
TPONA
11.5 Ω 1% 6
1:2
3
11
2
PAUI
AUTOSEL
NTH
DSQE
LI
MD2
MD1
MODE SELECT
MD0
330
Green Red
330
Red
78 Ω
CIN
9
1
1
1
16
9
2
2
CIP
330
Red
8
10
JAB
PLR
LINE STATUS
330
TPOPB
TPOPA
LXT908
PROGRAMMING
OPTIONS
220pF
11.5 Ω 1%
DON
78 Ω 4
3
15
11
4
13
12
5
LEDC/FDE
LEDR
LEDT/PDN
LEDL
5
12
78 Ω 7
10
DOP
DIN
D - CONNECTOR to
AUI DROP CABLE
TXD
20 pF
20 MHz
To 10 BASE-T TWISTEDPAIR NETWORK
20 pF
13
6
14
7
15
8
TEST
+3.3V
DIP
RBIAS
1 %
GND1
Fuse
9
12.4 kΩ
VCC1
VCC2
1
8
GND2
1
Chassis
Gnd
+ 12 V
Bias resistor RBIAS should be located close to the pin and isolated from other signals.
13
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Full Duplex Support
doubling the available bandwidth of the network. In this
application the SQE function is enabled (DSQE tied Low),
and the LXT908 AUI port is not used.
Figure 9 shows the LXT908 with a Texas Instruments
380C24 CommProcessor. The 380C24 is compatible with
Mode 4 (MD2:0 = Low, High, High). When used with the
380C24 or other full duplex-capable controller, the
LXT908 supports full-duplex Ethernet, effectively
Figure 9: Full-Duplex Operation
CLKI
3
20 pF
20 MHz
CLKO
RJ45
TXD
LPBK
*TEST0
OUTSEL0
1N914
1
TEN
TCLK
RCLK
TPIN
RXD
CD
TPIP
COL
LBK
LEDC/FDE
10 KΩ
AUTOSEL
*Open Collector
Driver
NTH
1
1 : 1 16
6
100 Ω
5
14
3
4
TPONB
LXT908
TXD
TXEN
TXC
RXC
RXD
CSN
COLL
TPONA
11.5 Ω 1% 6
1:2
11
2
220pF
TPOPB
TPOPA
11.5 Ω 1%
3
8
To 10 BASE-T TWISTEDPAIR NETWORK
20 pF
TMS380C24
9
1
4.7 KΩ
PROGRAMMING
OPTIONS
LI
DSQE
PAUI
MD2
CIN
CIP
MODE
SELECT
MD1
MD0
LINE STATUS
JAB
PLR
DON
PAUI
DOP
330
330
Green R e d
Red
330
LEDR
LEDT/PDN
LEDL
1
Half/Full Duplex Selection controlled by TMS380C24 Pin
Test0 and OUTSEL0.
2
Bias resistor RBIAS should be located close to the pin
and isolated from other signals.
3
The TMS380C26 may be substituted for dual network
support of 10BASE-T and Token Ring.
DIN
DIP
TEST
+3.3 V
VCC1
2
12.4 kΩ
RBIAS
1 %
VCC2
GND1 GND2
14
LXT908 Application Information
Dual Network Support-10Base T and Token Ring
Figure 10 shows the LXT908 with a Texas Instruments
380C26 CommProcessor. The 380C26 is compatible with
Mode 4 (MD2:0 = Low, High, High).
When used with the 380C26, both the LXT908 and a
TMS38054 Token Ring transceiver can be tied to a single
RJ-45 allowing dual network support from a single
connector. The LXT908 AUI port is not used.
Figure 10: LXT908/380C26 Interface for Dual Network Support of 10BASE-T and Token Ring
From TI TMS38054 Token
Ring Transceiver
To TI TMS38054 Token Ring
Transceiver
380C26
CLKI
TXD
TXD
TXE
TXC
RXC
RXD
CRS
COL
LBK
CLKO
2
1
TPIN
TEN
100 Ω
RXD
CD
COL
TPONB
JAB
LINE STATUS
330
330
Green Red
Red
Red
11
TPOPA
11.5 Ω 1%
3
2
220pF
8
9
1
TPOPB
18 p F
CIN
PLR
330
11.5 Ω 1% 6 1 : 2
TPONA
LXT908
MODE SELECT
14
4
AUTOSEL
NTH
DSQE
PAUI
LI
MD1
MD0
5
3
TPIP
LBK
MD2
RJ45
1 : 1 16
6
TCLK
RCLK
PROGRAMMING
OPTIONS
330
20 pF
20 MHz
To 10 BASE-T TWISTEDPAIR NETWORK
20 pF
CIP
1
LEDC/FDE
LEDR
LEDT/PDN
LEDL
DON
2
DOP
Bias resistor RBIAS should be located close to the pin
and isolated from other signals.
Additional magnetics and switching logic (not shown)
is required to implement the dual network solution.
DIN
DIP
TEST
+3.3 V
12.4 kΩ
VCC1
RBIAS
VCC2
1 %
GND1
GND2
1
15
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Manual Port Select & Link Test Function
With MD2:0 = Low, High, Low, the LXT908 logic and
framing are set to Mode 3 (compatible with Fujitsu
MB86950 and MB86960, and Seeq 8005 controllers).
Figure 11 shows the setup for Fujitsu controllers.
Figure 12 on page 17 shows the four inverters required to
interface with the Seeq 8005 controller. As in Figure 8 on
page 13, both these Mode 3 applications show the LI pin
tied High, enabling Link Testing; and the NTH and DSQE
pins are both tied High, selecting the standard receiver
threshold and disabling SQE.
However, in these
applications AUTOSEL is tied Low, allowing external port
selection through the PAUI pin.
Figure 11: LAN Adapter Board - Manual Port Select with Link Test Function
20 pF
20 pF
20 MHz
TCKN
MB86950 or MB86960
BACK-END/
CONTROLLER
INTERFACE
RCKN
RXD
XCD
XCOL
LBC
Port Selection
Green
Red
6
100 Ω
5
TPIP
4
TPONB
11.5 Ω 1%
TPONA
6
Red
1:2
3
11
2
220pF
11.5 Ω 1%
8
9
1
LXT908
TPOPA
TPOPB
78 Ω
CIN
1
1
16
9
2
10
330
Red
14
3
LBK
PAUI
AUTOSEL
PLR
330
16
CD
COL
JAB
LINE STATUS
1:1
TPIN
TCLK
RCLK
RXD
MD2
MD1
MD0
MODE
SELECT
330
RJ45
1
NTH
DSQE
LI
PROGRAMMING
OPTIONS
330
CLKO
2
CIP
LEDC/FDE
LEDR
LEDT/PDN
LEDL
78 Ω
DON
3
15
11
4
4
13
12
5
DOP
78 Ω
DIN
5
12
7
10
D - CONNECTOR to
AUI DROP CABLE
TEN
CLKI
TXD
TEN
To 10 BASE-T TWISTEDPAIR NETWORK
TXD
13
6
14
7
15
8
TEST
+3.3 V
8
DIP
12.4 kΩ
VCC1
RBIAS
VCC2
1 %
GND1
GND2
1
1
16
Fuse
9
Chassis
Gnd
+ 12 V
Bias resistor RBIAS should be located close to the pin and isolated from other signals.
LXT908 Application Information
Figure 12: Manual Port Select with Seeq 8005 Controller
External
20 MHz
Source
Left Open
CSN
8005
CLKO
CLKI
LBK
CD
RxD
RJ45
1
COLL
6
100 Ω
TxC
TxD
PROGRAMMING
OPTIONS
14
TPIP
4
TPONB
PAUI
AUTOSEL
NTH
DSQE
LI
Port Selection
5
3
COL
TEN
TCLK
TXD
TxEN
16
TPIN
RXD
RCLK
RxC
1:1
11.5 Ω 1% 6
TPONA
1:2
3
11
2
220pF
11.5 Ω 1%
TPOPA
8
To 10 BASE-T TWISTEDPAIR NETWORK
CLKI
LPBK
9
1
TPOPB
MD1
MD0
LINE STATUS
JAB
PLR
330
330
330
78 Ω
CIN
1
1
Red
Red
Red
9
2
10
330
2
Green
16
LEDC/FDE
LEDR
LEDT/PDN
LEDL
TEST
CIP
78 Ω
DON
3
15
11
4
4
13
12
5
DOP
78 Ω
DIN
5
12
7
10
D - CONNECTOR to
AUI DROP CABLE
MODE SELECT
LXT908
MD2
13
6
14
7
15
8
8
DIP
VCC1
+3.3V
RBIAS
VCC2
12.4 kΩ
1 %
GND1 GND2
1
1
Fuse
9
Chassis
Gnd
+ 12 V
Bias resistor RBIAS should be located close to the pin and isolated from other signals.
17
18
1
CLKO
12.4 kΩ
1%
RBIAS
VCC2
VCC1
TEST
LEDL
LEDT/PDN
LEDR
LEDC/FDE
PLR
JAB
MD0
MD1
MD2
LI
PAUI
DSQE
NTH
AUTOSEL
LBK
COL
CD
RXD
RCLK
TCLK
TEN
TXD
CLKI
GND1
LXT908
0.1 µF
+3.3 V
10 k Ω
LBK
CDT
CRS
RXD
RXC
RTS
TXC
CLK
TXD
GND2
DIP
DIN
DOP
DON
CIP
CIN
TPOPB
TPOPA
TPONA
TPONB
TPIP
TPIN
11.5 Ω 1%
11.5 Ω 1%
100 Ω
8
6
3
1
1:2
1:1
9
11
14
16
78 Ω
78 Ω
78 Ω
1
2
3
4
5
6
9
8
10
9
8
12
13
15
7
5
4
2
16
10
7
1
12
5
13
15
2
4
16
To 10 BASE-T
TWISTEDPAIR
NETWORK
1
RJ45
8
7
6
5
4
3
2
Chassis
Gnd
15
14
13
12
11
10
9
1
1.5 kΩ
+ 12 V
Fuse
D - CONNECTOR to
AUI DROP CABLE
(Thick Coax)
HBE
GND
RXRX+
RR+
RR-
VEE
TX+
VEE
VEE
RXI
TXD
CD+
TX-
CDS
CD-
DP8392
0.01 µF
1 MΩ
1/2 W
-9V
1 kΩ 1%
1N916
0V
9
13
12
V-
N/C
V+
24
23
3
1
2
75 µF / 1 kV
GND
GND
EN
5V
5V
PM6044
BHC to THIN
COAX
NETWORK
+5 V
Figure 13 shows the LXT908 in Mode 2 (compatible with
Intel 82596 controllers) with additional media options for
the AUI port.
Power Down
10 k Ω
LINE STATUS
MODE SELECT
LINK TEST
ENABLE
PROGRAMMING
OPTIONS
82566 BACK-END/
CONTROLLER
INTERFACE
20 MHz
System
Clock
Left Open
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Three Media Application
Two transformers are used to couple the AUI port to either
a D-connector or a BNC connector. (A DP8392 coax
transceiver with PM6044 power supply are required to
drive the thin coax network through the BNC.)
Figure 13: Three Media Application
LXT908 Application Information
AUI Encoder/Decoder Only
In the application shown in Figure 14, the DTE is
connected to a coaxial network through the AUI.
AUTOSEL is tied Low and PAUI is tied High, manually
selecting the AUI port. The twisted-pair port is not used.
With MD2:0 all tied Low, the LXT908 logic and framing
are set to Mode 1 (compatible with AMD and Motorola
controllers). The LI pin is tied Low, disabling the link test
function. The DSQE pin is also Low, enabling the SQE
function. The LBK input controls loopback. A 20 MHz
system clock is supplied at CLKI with CLKO left open.
Figure 14: AUI Encoder/Decoder Only Application
Left Open
20 MHz
TX
TENA
TCLK
RCLK
AM7990 BACK-END/
CONTROLLER
INTERFACE
RX
RENA
CLSN
LOOPBACK
CONTROL
LBK
CLKI
CLKO
TXD
TEN
TCLK
RCLK
RXD
CD
COL
LBK
AUTOSEL
78 Ω
PAUI
MODE SELECT
JAB
PLR
LINE STATUS
330
330
16
9
10
2
CIP
LXT908
MD2
MD1
MD0
1
1
2
NTH
DSQE
LI
PROGRAMMING
OPTIONS
330
CIN
DON
78 Ω 4
3
15
11
4
13
12
5
5
12
78 Ω 7
10
DOP
DIN
330
13
6
14
D - CONNECTOR to
AUI DROP CABLE
SYSTEM
CLOCK
7
15
8
GREEN
Red
Red
Red
LEDC/FDE
LEDR
LEDT/PDN
LEDL
8
DIP
Fuse
9
Chassis
Gnd
TEST
+3.3 V
VCC1
+ 12 V
1
RBIAS
VCC2
12.4 kΩ
1 %
GND1 GND2
1
Bias resistor RBIAS should be located close to the pin and isolated from the other signals
19
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
TEST SPECIFICATIONS
NOTE
Tables 4 through 13 and Figures 15 through 44 represent the performance specifications of the LXT908. These
specifications are guaranteed by test except where noted “by design.” Minimum and maximum values listed in
Tables 6 through 13 apply over the recommended operating conditions specified in Table 5.
.
Table 4:
Absolute Maximum Values
Parameter
Symbol
Min
Max
Units
VCC
-0.3
6
V
Ambient operating temperature (Commercial)
TA
0
+70
ºC
Ambient operating temperature (Extended)
TA
-40
+85
ºC
TSTG
-65
+150
ºC
Supply voltage
Storage temperature
CAUTION
Exceeding these values may cause permanent damage.
Functional operation under these conditions is not implied.
Exposure to maximum rating conditions for extended periods may affect device reliability.
Table 5:
Recommended Operating Conditions
Parameter
Symbol
Min
Typ
Max
Units
Recommended supply voltage1
VCC
3.13
3.3
3.47
V
Recommended operating temperature (Commercial)
TOP
0
–
+70
ºC
Recommended operating temperature (Extended)
TOP
-40
–
+85
ºC
1. Voltages with respect to ground unless otherwise specified.
20
LXT908 Test Specifications
Table 6:
I/O Electrical Characteristics
Sym
Min
Typ1
Max
Units
Input Low voltage2
VIL
–
–
0.8
V
Input High voltage2
VIH
2.0
–
–
V
Output Low voltage
VOL
–
–
0.4
V
IOL = 1.6 mA
VOL
–
–
10
%VCC
IOL < 10 µ A
Output Low voltage
(Open drain LED driver)
VOLL
–
–
0.7
V
IOLL = 10 mA
Output High voltage
VOH
2.4
–
–
V
IOH = 40 µ A
VOH
90
–
–
%VCC
IOH < 10 µ A
CLOAD = 20 pF
Parameter
Test Conditions
Output rise time
CMOS
–
–
3
12
ns
TCLK & RCLK
TTL
–
–
2
8
ns
Output fall time
CMOS
–
–
3
12
ns
TCLK & RCLK
TTL
–
–
2
8
ns
CLKI rise time (externally driven)
–
–
–
10
ns
CLKI duty cycle (externally driven)
–
–
40/60
%
ICC
–
65
85
mA
Idle Mode
ICC
–
95
120
mA
Transmitting on TP
ICC
–
90
120
mA
Transmitting on AUI
ICC
–
0.75
2
mA
Supply current
Normal Mode
Power Down Mode
CLOAD= 20 pF
1. Typical values are at 25 °C and are for design aid only; not guaranteed and not subject to production testing.
2. Limited functional tests are performed at these input levels. The majority of functional tests are performed at levels of 0V and 3V.
Table 7:
AUI Electrical Characteristics
Symbol
Min
Typ1
Max
Units
Input Low current
IIL
–
–
-700
µA
Input High current
IIH
–
–
500
µA
Differential output voltage
VOD
±550
–
±1200
mV
Differential squelch threshold
VDS
150
260
350
mV
Parameter
Test Conditions
5 MHz square wave input
1. Typical values are at 25 °C and are for design aid only; not guaranteed and not subject to production testing.
21
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Table 8:
Twisted-Pair Electrical Characteristics
Symbol
Min
Typ1
Max
Units
ZOUT
–
5
–
Ω
Transmit timing jitter addition2
–
–
±6.4
±10
ns
0 line length for internal MAU
Transmit timing jitter added by the
MAU and PLS sections2, 3
–
–
±3.5
±5.5
ns
After line model specified by
IEEE 802.3 for 10BASE-T
internal MAU
Receive input impedance
ZIN
–
20
–
kΩ
Between TPIP/TPIN, CIP/
CIN & DIP/DIN
Differential Squelch
Threshold
Normal
Threshold
NTH =
High
VDS
300
395
585
mV
5 MHz square wave input
Reduced
Threshold
NTH =
Low
VDS
180
250
345
mV
5 MHz square wave input
Parameter
Transmit output impedance
Test Conditions
1. Typical values are at 25 °C and are for design aid only; not guaranteed and not subject to production testing.
2. Parameter is guaranteed by design; not subject to production testing.
3. IEEE 802.3 specifies maximum jitter additions at 1.5 ns for the AUI cable, 0.5 ns from the encoder, and 3.5 ns from the MAU.
22
LXT908 Test Specifications
Table 9:
Switching Characteristics
Symbol
Minimum
Typical1
Maximum
Units
Maximum transmit time
–
20
–
150
ms
Unjab time
–
250
–
750
ms
Time link loss receive
–
50
–
150
ms
Link min receive
–
2
–
7
ms
Link max receive
–
50
–
150
ms
Link transmit period
–
8
10/20
24
ms
Parameter
Jabber Timing
Link Integrity
Timing
1. Typical values are at 25 °C and are for design aid only; not guaranteed and not subject to production testing.
Table 10: RCLK/Start-of-Frame Timing
Symbol
Minimum
Typical1
Maximum
Units
tDATA
–
900
1100
ns
tDATA
–
1200
1500
ns
AUI
tCD
–
25
200
ns
TP
tCD
–
420
550
ns
Receive data setup from
RCLK
Mode 1
tRDS
60
70
–
ns
Modes 2 through 5
tRDS
30
45
–
ns
Receive data hold from
RCLK
Mode 1
tRDH
10
20
–
ns
Modes 2 through 5
tRDH
30
45
–
ns
RCLK shut off delay from CD assert (Mode 3
and Mode 5)
tsws
–
±100
–
ns
Parameter
Decoder acquisition time AUI
TP
CD turn-on delay
1. Typical values are at 25° C and are for design aid only; not guaranteed and not subject to production testing.
23
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Table 11: RCLK/End-of-Frame Timing
Type
Sym
Mode
1
Mode
2
Mode
3
Mode
4
Mode
5
Units
RCLK after CD off
Min
tRC
5
1
–
5
–
BT
RXD throughput delay
Max
tRD
400
375
375
375
375
ns
CD turn off delay2
Max
tCDOFF
500
475
475
475
475
ns
Receive block out after TEN off
Typ1
tIFG
5
50
–
–
–
BT
RCLK switching delay after CD off
(Mode 3 and 5)
Typ1
tSWE
–
–
120(±80)
–
120(±80)
ns
Parameter
1. Typical values are at 25° C and are for design aid only; not guaranteed and not subject to production testing.
2. CD turn-off delay measured from middle of last bit: timing specification is unaffected by the value of the last bit.
Table 12: Transmit Timing
Symbol
Minimum
Typical 1
Maximum
Units
TEN setup from TCLK
tEHCH
22
–
–
ns
TXD setup from TCLK
tDSCH
22
–
–
ns
TEN hold after TCLK
tCHEL
5
–
–
ns
TXD hold after TCLK
tCHDU
5
–
–
ns
Transmit start-up delay - AUI
tSTUD
–
220
450
ns
Transmit start-up delay - TP
tSTUD
–
430
450
ns
Transmit through-put delay - AUI
tTPD
–
–
300
ns
Transmit through-put delay - TP
tTPD
–
305
350
ns
Parameter
1. Typical values are at 25° C and are for design aid only; not guaranteed and not subject to production testing.
24
LXT908 Test Specifications
Table 13: Collision, COL/CI Output and Loopback Timing
Symbol
Minimum
Typical1
Maximum
Units
COL turn-on delay
tCOLD
–
40
500
ns
COL turn-off delay
tCOLOFF
–
420
500
ns
COL (SQE) Delay after TEN off
tSQED
0.65
1.2
1.6
µs
COL (SQE) Pulse Duration
tSQEP
500
1000
1500
ns
LBK setup from TEN
tKHEH
10
25
–
ns
LBK hold after TEN
tKHEL
10
0
–
ns
Parameter
1. Typical values are at 25° C and are for design aid only; not guaranteed and not subject to production testing.
25
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Timing Diagrams for Mode 1 (MD2, 1, 0 = Low, Low, Low)
Figures 15 through 20
Figure 15: Mode 1 RCLK/Start-of-Frame Timing
1
0
1
0
1
0
1
0
1
1
1
0
1
0
0
0
1
0
1
0
0
1
0
1
1
1
TPIP/TPIN
or DIP/DIN
tC D
CD
RCLK
tR D S
tR D H
tD A T A
RXD
1
0
1
0
1
0
1
NOTE: RXD changes 25 ns after the rising edge of RCLK.
Figure 16: Mode 1 RCLK/End-of-Frame Timing
1
0
1
0
1
0
1
0
0
TPIP/TPIN
or DIP/DIN
tC D O F F
CD
tR D
tR C
RCLK
RXD
1
0
1
0
1
0
1
0
0
NOTE: RXD changes 25 ns after the rising edge of RCLK.
26
LXT908 Test Specifications
Figure 17: Mode 1 Transmit Timing
TEN
tC H E L
tE H C H
TCLK
tD S C H
tC H D U
TXD
tS T U D
tT P D
TPO
Figure 18: Mode 1 Collision Detect Timing
CI
tC O L O F F
tC O L D
COL
Figure 19: Mode 1 COL/SQE Output Timing/CI Output Timing
TEN
tS Q E D
COL
tS Q E P
Figure 20: Mode 1 Loopback Timing
LBK
tK H E H
tK H E L
TEN
27
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Timing Diagrams for Mode 2
(MD2, 1, 0 = Low, Low, High) Figures 21 through 26
Figure 21: Mode 2 RCLK/Start-of-Frame Timing
1
0
1
0
1
0
1
0
1
1
1
0
1
0
0
0
1
0
1
0
0
1
0
1
1
1
TPIP/TPIN
or DIP/DIN
tC D
CD
RCLK
tR D S
tR D H
tD A T A
RXD
1
0
1
0
1
0
1
NOTE: RXD changes at the rising edge of RCLK. The controller should sample at the falling edge.
Figure 22: Mode 2 RCLK/End-of-Frame Timing
1
0
1
0
1
0
1
0
0
TPIP/TPIN
or DIP/DIN
CD
tC D O F F
tR D
RCLK
RXD
1
0
1
0
1
0
1
0
0
NOTE: RXD changes at the rising edge of RCLK. The controller should sample at the falling edge.
28
LXT908 Test Specifications
Figure 23: Mode 2 Transmit Timing
TEN
tC H E L
tE H C H
TCLK
tD S C H
tC H D U
TXD
tS T U D
tTPD
TPO
Figure 24: Mode 2 Collision Detect Timing
CI
tC O L D
tC O L O F F
COL
Figure 25: Mode 2 COL/SQE Output Timing
tIFG
TEN
tS Q E D
COL
tS Q E P
Figure 26: Mode 2 Loopback Timing
LBK
tK H E H
tK H E L
TEN
29
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Timing Diagrams for Mode 3 (MD2, 1, 0 = Low, High, Low)
Figures 27 through 32
Figure 27: Mode 3 RCLK/Start-of-Frame Timing
1
0
1
0
1
0
1
0
1
1
1
0
1
0
0
0
1
0
1
TPIP/TPIN
or DIP/DIN
tC D
CD
tS W S
Recovered from Input Data Stream
RCLK
tR D S
Generated from TCLK
tR D H
tD A T A
RXD
1
0
1
0
1
0
1
0
1
1
1
0
1
NOTE: RXD changes at the rising edge of RCLK. The controller should sample at the falling edge.
Figure 28: Mode 3 RCLK/End-of-Frame Timing
1
0
1
0
1
0
1
0
0
TPIP/TPIN
or DIP/DIN
tC D O F F
CD
tR D
tS W E
RCLK
Recovered Clock
Generated from TCLK
RXD
1
0
1
0
1
0
1
0
0
NOTE: RXD changes at the rising edge of RCLK. The controller should sample at the falling edge.
30
LXT908 Test Specifications
Figure 29: Mode 3 Transmit Timing
TEN
tC H E L
tE H C H
TCLK
tD S C H
tC H D U
TXD
tS T U D
tT P D
TPO
Figure 30: Mode 3 Collision Detect Timing
CI
tC O L O F F
tC O L D
COL
Figure 31: Mode 3 COL/SQE Output Timing
TEN
tS Q E D
tS Q E P
COL
Figure 32: Mode 3 Loopback Timing
LBK
tK H E H
tK H E L
TEN
31
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Timing Diagrams for Mode 4
(MD2, 1, 0 = Low, High, High) Figures 33 through 38
Figure 33: Mode 4 RCLK/Start-of-Frame Timing
1
0
1
0
1
0
1
0
1
1
1
0
1
0
0
0
1
0
1
TPIP/TPIN
or DIP/DIN
tC D
CD
RCLK
tR D S
tR D H
tD A T A
RXD
1
0
1
0
1
0
1
0
1
1
1
0
1
NOTE: RXD changes at the rising edge of RCLK. The controller should sample at the falling edge.
Figure 34: Mode 4 RCLK/End-of-Frame Timing
1
0
1
0
1
0
1
0
0
TPIP/TPIN
or DIP/DIN
tC D O F F
CD
tR D
RCLK
RXD
1
0
1
0
1
0
1
0
0
NOTE: RXD changes at the rising edge of RCLK. The controller should sample at the falling edge.
32
LXT908 Test Specifications
Figure 35: Mode 4 Transmit Timing
TEN
tC H E L
tE H C H
TCLK
tD S C H
tC H D U
TXD
tT P D
tS T U D
TPO
Figure 36: Mode 4 Collision Detect Timing
CI
tC O L D
tC O L O F F
COL
Figure 37: Mode 4 COL/SQE Output Timing
TEN
tS Q E D
COL
tS Q E P
Figure 38: Mode 4 Loopback Timing
LBK
tK H E H
tK H E L
TEN
33
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
Timing Diagrams for Mode 5 (MD2, 1, 0 = High, High, Low)
Figures 39 through 44
Figure 39: Mode 5 RCLK/Start-of-Frame Timing
1
0
1
0
1
0
1
0
1
1
1
0
1
0
0
0
1
0
1
TPIP/
TPIN
tC D
CD
tS W S
Recovered from Input Data Stream
RCLK
tR D S
Generated from TCLK
tR D H
tD A T A
RXD
1
0
1
0
1
0
1
0
1
1
1
0
1
NOTE: RXD changes at the rising edge of RCLK. The controller should sample at the falling edge.
Figure 40: Mode 5 RCLK/End-of-Frame Timing
1
0
1
0
1
0
1
0
0
TPIP/
TPIN
tC D O F F
CD
tR D
tS W E
RCLK
Recovered Clock
Generated from TCLK
RXD
1
0
1
0
1
0
1
0
0
NOTE: RXD changes at the rising edge of RCLK. The controller should sample at the falling edge.
34
LXT908 Test Specifications
Figure 41: Mode 5 Transmit Timing
TEN
tC H E L
tE H C H
TCLK
tD S C H
tC H D U
TXD
tS T U D
tT P D
TPO
Figure 42: Mode 5 Collision Detect Timing
CI
tC O L O F F
tC O L D
COL
Figure 43: Mode 5 COL/SQE Output Timing
TEN
tS Q E D
tS Q E P
COL
Figure 44: Mode 5 Loopback Timing
LBK
tK H E H
tK H E L
TEN
35
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
MECHANICAL SPECIFICATIONS
Figure 45: 44-Pin PLCC Package Specifications
44-Pin Plastic Leaded Chip Carrier
• Part Number LXT908PC - Commercial temperature range (0°C to +70°C)
• Part Number LXT908PE - Extended temperature range (-40°C to +85°C)
CL
Inches
C
Millimeters
Dim
Min
Max
Min
Max
A
0.165
0.180
4.191
4.572
A1
0.090
0.120
2.286
3.048
A2
0.062
0.083
1.575
2.108
B
0.050
–
1.270
–
C
0.026
0.032
0.660
0.813
D
0.685
0.695
17.399
17.653
D1
0.650
0.656
16.510
16.662
F
0.013
0.021
0.330
0.533
B
D1
D
D
A2
A
A1
F
36
LXT908 Mechanical Specifications
Figure 46: 64-Pin LQFP Package Specifications
64-Pin Low-Profile Quad Flat Package
• Part Number LXT908LC (Commercial Temperature Range)
• Part Number LXT908LE (Extended Temperature Range)
D
D1
Inches
Millimeters
Dim
Min
Max
Min
Max
A
–
0.063
–
1.60
A1
0.002
0.006
0.05
0.15
A2
0.053
0.057
1.35
1.45
B
0.007
.011
0.17
0.27
D
0.472 BSC
12.00 BSC
D1
0.394 BSC
10.00 BSC
E
0.472 BSC
12.00 BSC
E1
0.394 BSC
10.00 BSC
e
0.020 BSC
0.50 BSC
L
0.018
L1
θ3
θ
0.030
0.039 REF
11
o
0o
13
0.45
E1
e
/2
0.75
1.00 REF
o
7o
11o
13o
0o
7o
θ3
L1
A2
A
A1
L
e
E
B
θ
θ3
37
LXT908 Universal 3.3V 10BASE-T and AUI Transceiver
REVISION HISTORY
Table 14: Changes from Revision 1.5 to Revision 1.6 (03/00)
Section
Page
Change
Text
Table 1
4
Modify
Add to LEDT/PDN Description: “Do not allow this pin to
float. If unused, tie High.”
LXT908 Signal
Descriptions
Table 15: Changes from Revision 1.4 to Revision 1.5 (01/99)
Section
Page
Change
Text
Front Page
1
Update
Delete 5V reference in general description and features
list.
Table 1
4
Update
Delete 5V reference to supply pins.
12
Update
Delete Magnetics Table 4 (renumber all subsequent tables)
and reference Application Note 73.
Layout Requirements
12
Update
Add power and ground pins (VCCA and GNDA) for 64Pin LQFP package.
Figures 13, 14
18, 19
Update
Correct RBIAS value to 12.4 kΩ in diagrams.
Signal Descriptions
Table 4
Magnetics
Application Diagrams
Figures 8 - 14
Delete Note 1 in Figure 13 (duplication RBIAS placement).
13 - 19
Update
Delete 5V supply reference (3.3V only).
20
Update
Change recommended supply voltage:
Application Diagrams
Table 6
Recommended Operating
Conditions
(Min to Max respectively)
From: 3.135 5.0 5.25V
To: 3.13 3.3 3.47V
All
All
Edit
Various minor editing.
Table 16: Changes from Revision 1.3 to Revision 1.4 (09/98)
Section
Page
Change
Text
Product Title
1
Update
Change product name to Universal 10BASE-T and AUI
Transceiver.
Table 1
4
Update
Correct pin 9 of the LQFP package to include 3.3V supply.
20-25
Update
Replace test spec note with updated version and delete
Signal Descriptions
Test Specifications
(over recommended range) note on all test spec tables.
Backpage
38
40
Update
Update backpage.
LXT908 Revision History
Table 17: Changes from Revision 1.2 to Revision 1.3 (04/98)
Section
Page
Change
Text
Front Page
1
Update
Add 64-pin LQFP to features list.
Figure 1
3
Update
Add 64-pin LQFP pin assignment diagram.
4
Update
Add LQFP package column and pins.
35
Update
Add 64-pin LQFP package diagram.
Pin Assignments
Table 1
Signal Descriptions
Figure 46
Package Diagram
Table 18: Changes from Revision 1.1 to Revision 1.2 (03/98)
Section
Page
Change
Text
Front Page
1
Update
Add Commercial (0 to +70°C) and
extended (-40 to +85°C) temperature range to Features list.
Figure 1
3
Update
Add “PE” to package designator for extended temperature.
18
Update
Add extended temperature (-40 to +85°C).
34
Update
Add part number LXT908PE and extended temperature
range (-40 to +85°C).
35
Update
Add revision history section.
Pin Assignments
Tables 5 and 6
Absolute Max Values
Operating Conditions
Figure 45
Package Diagram
Revision History
Table 19: Changes from Revision 1.0 to Revision 1.1 (10/97)
Section
Page
Change
Text
Table 1
4&5
Update
Change note for no connect pins #7 and #29. This pin may
be left unconnected or tied to ground.
10
Update
Change Belfuse AUI magnetic part number from
S553-1006-AE to S553-1006-D0.
Signal Descriptions
Table 4
Suitable Magnetics
39
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Revision
Date
Status
1.6
03/00
Add to LEDT/PDN Description: “Do not allow this pin to float. If unused, tie High.”
Information in this document is provided in connection with Level One products. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Level One's Terms and Conditions of Sale for such products, Level One assumes no liability whatsoever, and Level One disclaims any express or implied warranty, relating to sale and/or use of Level One products including liability or warranties relating to fitness
for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. Level One products are not interned for use
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Level One may make changes to specifications and product descriptions at any time, without notice. Designers must not rely on the absence or characteristics of
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The products listed in this publication are covered by one or more of the following patents. Additional patents pending.
5,008,637; 5,028,888; 5,057,794; 5,059,924; 5,068,628; 5,077,529; 5,084,866; 5,148,427; 5,153,875; 5,157,690; 5,159,291; 5,162,746; 5,166,635; 5,181,228;
5,204,880; 5,249,183; 5,257,286; 5,267,269; 5,461,661; 5,493,243; 5,534,863; 5,574,726; 5,581,585; 5,608,341; 5,666,129; 5,671,249; 5,701,099; 5,717,714;
5,742,603; 5,748,634; 5,764,638; 5,777,996; 5,802,052; 5,880,645; 5,881,074; 5,907,553; 5,926,049; 5,926,504; 5,946,398
Copyright © 2000 Level One Communications, Inc., an Intel Company. Specifications subject to change without notice. All rights reserved.
IS908DS-R1.6-0300