IPC@CHIP SC123/SC143
Hardware Manual V1.06 [18.02.2010]
©2000-2008 BECK IPC GmbH Page 51
9.2 Routing and placement rules for Ethernet components
Place the RJ45 connector, the magnetics and the SC1x3 as close together as possible. If this is not
possible, keep the RJ45 and the magnetics as close as possible. This will allow remote placement of the
SC1x3.
Select and place the magnetics as the best routing scheme from the SC1x3 to the magnetics to the RJ45
connector.
Place the 49.9 TX and RX termination pull-ups as close to the magnetics as possible.
Place the 75 cable side centre tap termination resistors and the 1nF capacitor as close to the magnetics
as possible.
Place the unused Wire Pair termination resistors and the 1nF capacitor as close to the RJ45 connector as
possible.
The traces connecting the transmit outputs (TXP and TXN) to the magnetics, must be run as differential
pairs. The differential impedance should be 100 .
The traces connecting the transmit outputs from the magnetics to pins 1 & 2 on the RJ45 connector must be
run as differential pairs. The differential impedance should be 100 .
The traces connecting the receive inputs (RXP and RXN) from the magnetics, must be run as differential
pairs. The differential impedance should be 100 .
The traces connecting the receive inputs on the magnetics from pins 3 & 6 on the RJ45 connector must be
run as differential pairs. The differential impedance should be 100 .
Typically, all planes are cleared out from under the differential pairs connecting the RJ45 and the magnetics.
The plane clear out boundary is usually halfway through the magnetics.
Trace impedance depends upon many variables (PCB construction, trace width, trace spacing, etc.). The
electrical engineer needs to work with the PCB designer to determine all these variables.
Try to keep all other signals out of the Ethernet front end (RJ45 through the magnetics to the IPC@CHIP).
Any noise from other traces may couple into the Ethernet section and cause problems.
9.3 Suggested Magnetics
BECK-IPC GmbH Part no. Magnetic FS23 (online shop ordering number: 538431)
BECK-IPC GmbH Part no. Magnetic FM24 (online shop ordering number: 556366)
Halo Electronics, Inc. Part no. TG110-S050N2 (http://www.haloelectronics.com)
UMEC Europe Part no. LU1S041-34-LF (http://www.umeu.de/)
TAIMAG Part no. RJSL-003TC1 (http://www.taimag.com/)
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