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21143 PCI/CardBus 10/100Mb/s Ethernet LAN Controller
12 Design Guide
Figure 5 shows the minimum component requirement for the 10BASE-T network connection. This
implementation uses a filter transformer module with a 1: transformer on the transmit path to
compensate for the voltage swing. The required components for this configuration are as follows:
• Terminating and decoupling components
• Filter, transformer, and common-mode chokes
• RJ45 connector
3.2 100-Ready Designs
The 21143 can also be designed for systems that are “100-Ready.” The term “100-Ready” implies
a system that has a 10 Mb/s network that can easily be upgraded to become a 10/100 Mb/s network.
There are two methods for providing 100-Ready designs:
• Provide a connector for an internal optional daughtercard.
• Provide an MII connector for an external module that connects to the MII/SYM port.
These two methods are described in Table 6.
2
Figure 5. Minimum Components Required for 10BASE-T
GND
27 Ω
140 Ω
27 Ω
140 Ω
510 Ω
TP Filters
and Chokes
78Z1122 or
FD22-114G
(SMD)
RJ45
GND
1
2
3
6
49.9 Ω
49.9 Ω
0.01 µF
LJ-05143.WMF
0.1 µF
GND
tp_td+ 6
tp_td++ 7
tp_td- 5
tp_td-- 4
tp_rd- 9
tp_rd- 10
21143
Transmit
Path
Receive
Path