Data Sheet
FEBRUARY 2000
Revision 1.1
LXT971
3.3V Dual-Speed Fast Ethernet Transceiver
General Description
Features
The LXT971 is an IEEE compliant Fast Ethernet PHY
Transceiver that directly supports both 100BASE-TX and
10BASE-T applications. It provides a Media Independent
Interface (MII) for easy attachment to 10/100 Media
Access Controllers (MACs). The LXT971 also provides a
pseudo-ECL (PECL) interface for use with 100BASE-FX
fiber networks.
• 3.3V Operation.
The LXT971 supports full-duplex operation at 10 Mbps
and 100 Mbps. Its operating condition can be set using
auto-negotiation, parallel detection, or manual control.
• MII interface with extended register capability.
• Low power consumption (300 mW typical).
• Low-power “Sleep” mode.
• 10BASE-T and 100BASE-TX using a single RJ-45
connection.
• Supports auto-negotiation and parallel detection.
• Robust baseline wander correction performance.
• 100BASE-FX fiber optic capable.
The LXT971 is fabricated with an advanced CMOS
process and requires only a single 3.3V power supply.
• Standard CSMA/CD or full-duplex operation.
• Configurable via MDIO serial port or hardware
control pins.
Applications
• Integrated, programmable LED drivers.
• Combination 10BASE-T/100BASE-TX or
100BASE-FX Network Interface Cards (NICs)
• 64-pin Plastic Ball Grid Array (PBGA).
• LXT971BC - Commercial (0° to 70°C ambient).
• LXT971BE - Extended (-40° to 85°C ambient).
• 64-pin Low-profile Quad Flat Package (LQFP).
• LXT971LC - Commercial (0° to 70°C ambient).
• LXT971LE - Extended (-40° to 85°C ambient).
• 10/100 PCMCIA Cards
• Cable Modems and Set-Top Boxes
LXT971 Block Diagram
RESET
Register Set
Manchester
Encoder
TX_CLK
Parallel/Serial
Converter
TX PCS
TX_ER
Scrambler
& Encoder
10
OSP ™
100
Pulse
Shaper
TxSLEW<1:0>
TP
Driver
ECL
Driver
Auto
Negotiation
+
TPFOP
+
TP / Fiber
Out
JTAG
Collision
Detect
Clock
Generator
Media
Select
OSP ™
Adaptive EQ with
Baseline Wander
Cancellation
+
RXDV
CRS
RX_ER
RX PCS
R X D <3:0>
Carrier Sense
Data Valid
Error Detect
10
Manchester
Decoder
100
Decoder &
Descrambler
OSP ™
5
TDIO,
TMS,
TCK,
TRST
100TX
+
RX_CLK
Serial-toParallel
Converter
TPFON
-
Register
Set
L E D / C F G <3:1>
COL
REFCLK
Clock
Generator
TX_EN
T X D <3:0>
VCC
GND
PWRDWN
Pwr Supply
Management /
Mode Select
Logic
ADDR<4:0>
MDIO
MDC
MDINT
MDDIS
100FX
+
Slicer
TP / Fiber
In
TPFIP
TPFIN
SD/TP
10BT
-
Refer to www.level1.com for most current information.
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