cs89712 Cirrus Logic, Inc., cs89712 Datasheet - Page 161

• Manufacturer Part Number: cs89712
• Description: High-performance, Low-power System-on-chip With 10base-t Ethernet Controller
• Manufacturer: Cirrus Logic, Inc.

ETHERNET QUARTZ CRYSTAL REQUIREMENTS
must meet the following specifications)
DS502PP2
Parallel Resonant Frequency
Resonant Frequency Error (C
Resonant Frequency Change Over Operating Temperature
Crystal Capacitance
Motional Crystal Capacitance
Series Resistance
Shunt Capacitance
Notes: 1. If a center tap transformer is used on the RXD+ and RXD- inputs, replace the pair of Rr resistors with
2. The Rt and Rr resistors are ±1% tolerance.
3. The CS89712 Ethernet port supports 100 W unshielded twisted pair cables. The proper values of Rt
a single 2xRr resistor.
and Rr, for a given cable impedance, are shown below:
+
-
TXD +
TXD -
RXD+
RXD-
Cable Impedance ( )
Parameter
L
100
Rt
Rt
0.01 F
= 18 pF)
0.01 F
560 pF
Figure 37. 10Base-T Wiring
Rr
Rr
Rt ( )
8.2
1:1
1:2.5
Min
-50
-40
-
-
-
-
-
(If a 20 MHz quartz crystal is used, it
Rr ( )
RD +
TD +
RD -
TD -
49.9
0.022
Typ
20
-
-
-
-
-
1
2
3
6
Max
+50
+40
RJ45
18
50
7
CS89712
-
-
MHz
Ohm
Unit
ppm
ppm
pF
pF
pF
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