CS89712-CB View Datasheet(PDF) - Cirrus Logic

Part Name

Description

MFG CO.

CS89712-CB

High-Performance, Low-Power System-on-Chip with 10BASE-T Ethernet Controller

Cirrus Logic 

CS89712

ETHERNET QUARTZ CRYSTAL REQUIREMENTS (If a 20 MHz quartz crystal is used, it

must meet the following specifications)

Parameter

Min

Parallel Resonant Frequency

-

Resonant Frequency Error (CL = 18 pF)

-50

Resonant Frequency Change Over Operating Temperature

-40

Crystal Capacitance

-

Motional Crystal Capacitance

-

Series Resistance

-

Shunt Capacitance

-

Typ

20

-

-

-

0.022

-

-

Max

Unit

-

MHz

+50

ppm

+40

ppm

18

pF

-

pF

50

Ohm

7

pF

TXD + Rt

TXD -

Rt

560 pF

0.01 µF

1:2.5

RXD+

+

Rr

- RXD-

0.01 µF

Rr

1:1

TD +

1

TD -

2

RJ45

RD +

3

RD -

6

Notes: 1. If a center tap transformer is used on the RXD+ and RXD- inputs, replace the pair of Rr resistors with

a single 2xRr resistor.

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

and Rr, for a given cable impedance, are shown below:

Cable Impedance (Ω)

100

Rt (Ω)

8.2

Rr (Ω)

49.9

Figure 37. 10Base-T Wiring

DS502PP2

161

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