
LU3X31FT Single-Port 3 V
10/100 Ethernet Transceiver TX/FX
Preliminary Data Sheet
July 2000
6
Lucent Technologies Inc.
Pin Information
(continued)
Table 2. Fiber-Optic Transceiver Interface
Note: Smaller font indicates that the pin has multiple functions.
Table 3. Twisted-Pair Transceiver Control
Table 4. MII Interface
Pin
No.
68
69
4
3
1
2
Pin Name
I/O
Pin Description
FOTX+
FOTX–
FORX+
FORX–
FOSD+/
SRL10
FOSD–/
RPTR10CLK
O
Fiber-Optic Transmit Driver Pair.
These pins are used to transmit differen-
tial PECL level NRZI data to a fiber-optic transceiver.
Fiber-Optic Receive Pair.
These pins are used to receive differential PECL
level NRZI data from a fiber-optic transceiver.
Fiber-Optic Signal Detect Differential Input Pair.
While operating in fiber
mode, these pins are used to detect whether or not the fiber-optic receive
pairs are receiving valid signal levels. See Table 8 for SRL10 and
RPTR10CLK descriptions. If fiber and serial 10 modes are not being used,
tie pin 1 and 2 low.
I
I
Pin
No.
61
Pin Name
I/O
Pin Description
REF100
I
Reference Resistor for 100 Mbits/s Twisted-Pair Driver.
Connect this pin
to ground through a 301
resistor.
Reference Resistor for 10 Mbits/s Twisted-Pair Driver.
Connect this pin
to ground through a 4.64 k
resistor.
Twisted-Pair Transmitter 3-State.
A high on this pin will 3-state both the
twisted-pair and fiber outputs. Tie to ground in normal operation.
60
REF10
I
8
TPTXTR
I
Pin
No.
23
24
25
26
27
28
29
34
35
36
37
38
39
41
Pin Name
I/O
Pin Description
RXDV
RXER
RXD3
RXD2
RXD1
RXD0
RXCLK
TXEN
TXER
TXD3
TXD2
TXD1
TXD0
TXCLK
O
O
O
O
O
O
O
I
I
I
I
I
I
O
Receive Data Valid.
Signals the presence of data on RXD[3:0].
Receive Error.
Indicates a received coding error has occurred.
Receive Data[3].
Receive Data[2].
Receive Data[1].
Receive Data[0].
Receive Clock.
Transmit Enable.
Signals the presence of data on TXD[3:0].
Transmit Error.
Indicates a transmit coding error has occurred.
Transmit Data[3].
Transmit Data[2].
Transmit Data[1].
Transmit Data[0].
Transmit Clock.
This pin outputs during node mode only. For
100 Mbits/s repeater mode, all transmit related MII signals should be syn-
chronized to 25 MHz clock on XIN pin. See Table 8 for 10 Mbits/s repeater
mode clocking.
Carrier Sense/PHY Address[3].
This output pin indicates the carrier sense
condition. It is only active on receive while in repeater mode. See Table 5 for
PHY[3] description.
42
CRS/
PHY[3]
I/O
Note: Smaller font indicates that the pin has multiple functions.