CS8900-CQ3 Cirrus Logic, CS8900-CQ3 Datasheet - Page 120

• Manufacturer Part Number: CS8900-CQ3
• Description: Crystal LAN ISA Ethernet Controller
• Manufacturer: Cirrus Logic

7.5 10BASE-T WIRING
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120
CS8900A
If a center tap transformer is used on the RXD+ and RXD- inputs, replace the pair of Rr resistors with
a single 2xRr resistor.
The Rt and Rr resistors are ±1% tolerance.
The CS8900A supports 100, 120, and 150
and Rr, for a given cable impedence, are shown below:
Note: for 3.3V operation the turns ratio on TXD+ and TXD- is 1:2.5, rt is 8 for 100 cable and the
68pF cap changes to 560pF.
+
-
TXD +
TXD -
RXD+
RXD-
Cable Impedance ( )
Rt
Rt
0.01 F
100
120
150
CIRRUS LOGIC PRODUCT DATA SHEET
0.01 F
68 pF
Rr
Rr
unshielded twisted pair cables. The proper values of Rt
Rt ( )
24.3
30.1
37.4
1 :
1 : 1
2
Crystal LAN™ ISA Ethernet Controller
RD +
Rr ( )
TD +
TD -
RD -
49.9
60.4
75
1
2
3
6
RJ45
CS8900A
DS271PP3