5.0 Design Guidelines
5.1 TPI Network Circuit
Pulse H1102
Pulse H2019
Pulse J0011D21
Pulse J0011D21B
Figure 11 shows the recommended circuit for a 10/100
Mb/s twisted pair interface. To the right is a partial list of
recommended transformers. It is important that the user
realize that variations with PCB and component character-
istics requires that the application be tested to ensure that
the circuit meets the requirements of the intended applica-
tion.
Vdd
RD-
Vdd
COMMON MODE CHOKES
MAY BE REQUIRED.
49.9Ω
0.1µF
1:1
49.9
Ω
RD+
TD-
RD-
0.1µF*
0.1µF*
RD+
TD-
TD+
Vdd
RJ45
T1
49.9Ω
1:1
0.1µF
NOTE: CENTER TAP IS PULLED TO VDD
49.9
Ω
*PLACE CAPACITORS CLOSE TO THE
TRANSFORMER CENTER TAPS
TD+
All values are typical and are +/- 1%
PLACE RESISTORS AND
CAPACITORS CLOSE TO
THE DEVICE.
Figure 11. 10/100 Mb/s Twisted Pair Interface
33
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