
Product Brief
May 1998
LU3X51FT-J80 Single-Port
10/100 Ethernet Transceiver TX/FX
Overview
The LU3X51FT-J80 is a fully integrated 10/100 Mbit
physical layer device with transceiver. This part was
designed for 10/100 Mbit applications where board
space, cost, and power are at a premium and strin-
gent functional interoperability is a necessity. The
LU3X51FT-J80 is a powerful device for the forward
migration of legacy 10 Mbit products and non compli-
ant 100 Mbit devices. The LU3X51FT-J80 was
designed from the beginning to conform fully with all
pertinent specifications, from the ISO/IEC 11801 and
EIA/TIA 568 cabling guidelines to ANSI X3.263 TP-
PMD to IEEE* 802.3 ethernet specifications.
Features
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Single-chip integrated physical layer and trans-
ceiver for 10Base-T and/or 100Base-T functions
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IEEE* 802.3 compatible 10Base-T and 100Base-T
physical layer interface and ANSI X3.263 TP-PMD
compatible transceiver
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PECL interface for external FX transceiver
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Built-in analog 10 Mbit receive filter, removing the
need for external filters
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Built-in 10 Mbit transmit filter
* IEEEis a registered trademark of The Institute of Electrical and
Electronics Engineers, Inc.
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10 Mbit PLL exceeding tolerances for both pream-
ble and data jitter
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100 Mbit PLL, combined with the digital adaptive
equalizer, robustly handles variations in rise-fall
time, excessive attenuation due to channel loss,
duty-cycle distortion, cross talk, and baseline wan-
der
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Transmit rise-fall time manipulated to provide lower
emissions, amplitude fully compatible for proper
interoperability
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Programmable scrambler seed for better FCC
compliancy
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Selectable CIM, Class II support, and powerful MII
drivers for repeater applications
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IEEE* 802.3u Clause 28 compliant auto negotia-
tion for full 10M and 100M control
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Fully configurable via pins and management
accesses
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Extended management support with interrupt
capabilities
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PHY MIB support
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Symbol mode option
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Full LED support
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Low-power CMOS implementation
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80-pin QFP package