CS8952(2001) View Datasheet(PDF) - Cirrus Logic

Part Name

Description

Manufacturer

CS8952
(Rev.:2001)

CrystalLAN™ 100BASE-X and 10BASE-T Transceiver

Cirrus Logic 

CS8952

+5

CS8952

68 Ω

SIGNAL- 8

SIGNAL+ 9

191 Ω

TX_NRZ- 4

TX_NRZ+ 5

82 Ω

130 Ω

0.1 µF

49.9 Ω

+5

HFBR-5103

FIBER TRANS.

+5

+5

63.4 Ω

49.9 Ω

4

SD

1 µH

Ferrite Bead

0.1 µF 0.1 µF

5 RxVCC

1 µH

Ferrite Bead

0.1 µF 0.1 µF

6 TxVCC

7 TD-

8 TD+

82 Ω

RX_NRZ- 6

RX_NRZ+ 7

130 Ω

82 Ω

130 Ω

3 RD-

2 RD+

1 RxVEE

9 TxVEE

Figure 7. Recommended Connection of Fiber Port

TX_NRZ+/- termination components should be

placed as close to the fiber transceiver as possible,

while RX_NRZ+/- and SIGNAL+/- termination

components should be placed close to the CS8952.

The CS8952 100BASE-FX interface IO pins

(TX_NRZ+, TX_NRZ-, RX_NRZ+, RX_NRZ-,

SIGNAL+, and SIGNAL-) may be left unconnect-

ed if a fiber interface is not used.

7.3 Internal Voltage Reference

A 4.99 kΩ biasing resistor must be connected be-

tween the CS8952 RES pin and ground. This resis-

tor biases the internal analog circuits of the CS8952

and should be placed as close as possible to RES

pin. Connect the other end of this resistor directly

to the ground plane. Connect the adjacent CS8952

ground pins (pins 85 and 87) to the grounded end of

the resistor forming a “shield” around the RES con-

nection.

7.4 Clocking Schemes

The CS8952 may be clocked using one of three

possible schemes: using a 25 MHz crystal and the

internal oscillator, using an external oscillator sup-

64

CrystalLAN™ 100BASE-X and 10BASE-T Transceiver

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