PRELIMINARY
NetPHY-4LP-KT/12PT
12-Port Demonstration Kit for the Am79C875
DISTINCTIVE CHARACTERISTICS
n Evaluation board is configured for layout
demonstration
n Quad magnetics modules with 12-port RJ-45
dual-stack connector
n Compact step-and-repeat design ideal for multiport applications
n Single VDD plane, single VSS plane, with
appropriate decoupling capacitors
GENERAL DESCRIPTION
The NetPHY™-4LP Demonstration Kit provides an
easy-to-use tool for demonstrating the ease of design
and layout using the NetPHY-4LP Low Power Quad 10/
100 Ethernet Transceiver. This non-functional board
will show how easy it is for system designers to create
a four-port layout and to step-and-repeat the layout for
any number of ports (in multiples of 4). 24-, 36-, and 48port switch systems can easily be created without the
need for individual routing and layout, as traditionally
required.
The NetPHY-4LP demonstration board shows an actual layout for a 12-port system. The small size of each
NetPHY-4LP device results in significant board space
savings against other quad PHY devices, even against
hex and octal PHYs. Because the NetPHY-4LP is optimized for RMII switch applications, the package size is
drastically reduced to a 100-pin standard PQFP package. RMII reduces the number of pins required at the
PHY/ASIC interface to 7 pins per port. This is a savings
of 9 pins per port from the legacy MII interface. Less
pins also means lower pin and package costs for
ASICs.
The NetPHY-4LP device is pin-placement optimized for
switch applications. The RMII pins are located on the
side that interfaces to the ASIC, requiring very short
traces and minimizing outside interference that can affect high-speed signals. Also, LED and configuration
pins are placed on the sides of the NetPHY-4LP package, away from the high-speed data and control pins,
which they would affect otherwise. Furthermore, all the
transmit and receive differential pairs are located on
the magnetics side, and traces are very short and
direct to minimize signal attenuation.
To demonstrate compact layout and placement, the
NetPHY-4LP demonstration board provides the layout
from the PHY to the dual-stack RJ-45 connector, which
is the setup that more closely resembles what is used
in today’s system boxes. It is imperative that the layout
be clean and concise, since any kind of interference
significantly affects signal conditions. Therefore, the
layout provided in the demonstration kit is the most optimal in terms of noise and connectivity.
KIT CONTENTS
n NetPHY-4LP Demonstration board
n Schematics
n Bill of Materials
n Board artwork for all layers
n NetPHY-4LP device data sheet (PID 22236B)
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Trademarks
Copyright © 1999 Advanced Micro Devices, Inc. All rights reserved.
AMD, the AMD logo, and combinations thereof, and HomePNA and PCnet are trademarks of Advanced Micro Devices, Inc.
Product names used in this publication are for identification purposes only and may be trademarks of their respective companies.
Publication # 22360 Rev: A Amendment/0
Issue Date: April 1999