D A T A
S H E E T
Am79C875
NetPHY™ 4LP Low Power Quad 10/100-TX/FX Ethernet Transceiver
DISTINCTIVE CHARACTERISTICS
■
Four 10/100BASE-TX Ethernet PHY transceivers
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Supports RMII (Reduced MII) interface
■
125 meter (m) MLT-3 and Baseline Wander
operation
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Low power consumption
— 1.3 Watt (W) typical (1:1 magnetics)
— 1.2 W typical (1.25:1 magnetics)
■
Power management modes:
— Selectable 1:1 or 1.25:1 transmit transformer
— Unplugged - approximately 100 mW per port
— Power Down - approximately 3 mW per port
■
Single 3.3 V power supply with 5 V I/O tolerance
■
Patent-pending DC restoration technique
reduces baseline wander susceptibility
■
Full and half-duplex operation with full-featured
Auto-Negotiation function
■
Next Page register support
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Automatic Polarity Detection during Auto-
Negotiation and 10BASE-T signal reception
■
Unique scramble seed per port reduces EMI in
switch and repeater applications
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One port supports 100BASE-FX function
■
Supports Inter Packet Gap as low as 40 ns for
high throughput applications
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No external filters or chokes required
■
Compliant with IEEE 802.3 standards for
100BASE-TX, 100BASE-FX, and 10BASE-T
■
Built-in loopback and test modes
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Small 14 x 20 mm 100-pin PQR package
■
Small package allows side-by-side PHY layout
— Fits neatly behind quad magnetics
— Saves board space over larger 208 PQFP
packages
■
Support for Industrial Temperature
(-40°C to +85°C)
GENERAL DESCRIPTION
The NetPHY™ 4LP device is a highly integrated, low
power 10BASE-T/100BASE-TX/FX Quad Ethernet
transceiver. The NetPHY™ 4LP device includes
integrated RMII, ENDECs, Scrambler/Descrambler,
and full-featured Auto-Negotiation with support for Par-
allel Detection and Next Page. Port 3 can be config-
ured as a 100BASE-FX transmitter to output an NRZI
PECL level signal. Each receiver has an adaptive
equalizer/DC restoration circuit for accurate clock/data
recovery on the 100BASE-TX signal at different cable
lengths and can perform to 125 m and beyond.
The NetPHY™ 4LP device operates on a 3.3 V supply
and offers 5 V I/O tolerance for mixed signal designs.
Power consumption is 1.3 W typical for the device, or
0.3 W per port using 1:1 magnetics. The NetPHY™
4LP device can use 1.25:1 magnetics, which de-
creases transmit power consumption and reduces de-
vice power consumption to 1.2 W typical.
The NetPHY™ 4LP device offers an optimized pinout
for network applications. RMII pins can be routed di-
rectly to the MAC and TX/RX media pins are routed di-
rectly to the magnetics. Direct routing of high speed
traces is imperative for project system design and EMI
noise reduction.
The NetPHY™ 4LP device’s on-chip input filtering and
output waveshaping eliminates the need of external hy-
brid filters for media connection. Integrated LED logic
allows three LEDs per port to be driven directly. These
features greatly simplify the design of a 100BASE-X re-
peater/switch board, thus requiring minimum external
components.
For ease of system and chip setup and testing, the Net-
PHY™ 4LP device offers loopback and various ad-
vanced testing and monitoring capabilities.
The NetPHY™ 4LP device is available in the Commer-
cial (0°C to 70°C) or Industrial (-40°C to +85°C) tem-
perature ranges. The Industrial temperature range is
well suited to environment such as enclosures with re-
stricted air flow or outdoor equipment.
Publication# 22236 Rev: H Amendment/0
Issue Date: February 2003
Refer to AMD’s Website (www.amd.com) for the latest information.
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