Agere Systems Inc.

9

Data Sheet, Rev. 3

June 2001

Two-Cable Transceiver/Arbiter Device

FW802A Low-Power PHY IEEE

35

TPA0

−

Analog I/O Portn, Port Cable Pair A. TPAn is the port A connection to the twisted-

pair cable. Board traces from each pair of positive and negative differen-

tial signal pins should be kept matched and as short as possible to the

external load resistors and to the cable connector.

40

TPA1

−

34

TPB0+

Analog I/O Portn, Port Cable Pair B. TPBn is the port B connection to the twisted-

pair cable. Board traces from each pair of positive and negative differen-

tial signal pins should be kept matched and as short as possible to the

external load resistors and to the cable connector.

39

TPB1+

33

TPB0

−

Analog I/O Portn, Port Cable Pair B. TPBn is the port B connection to the twisted-

pair cable. Board traces from each pair of positive and negative differen-

tial signal pins should be kept matched and as short as possible to the

external load resistors and to the cable connector.

38

TPB1

−

37

TPBIAS0

Analog I/O Portn, Twisted-Pair Bias. TPBIAS provides the 1.86 V nominal bias

voltage needed for proper operation of the twisted-pair cable drivers and

receivers and for sending a valid cable connection signal to the remote

nodes.

42

TPBIAS1

7, 17,

26, 27, 62

—

30, 31,

43, 50, 51

—

device.

2, 14,

25, 56, 64

—

ground plane.

32, 49,

52, 53

—

impedance ground plane.

59

XI

—

Crystal Oscillator. XI and XO connect to a 24.576 MHz parallel resonant

fundamental mode crystal. Although, when a 24.576 MHz clock source is

used, it can be connected to XI with XO left unconnected. The optimum

values for the external shunt capacitors are dependent on the specifica-

tions of the crystal used. It is suggested that two 12 pF shunt capacitors

be used for a crystal with a specified 7 pF loading capacitance. For more

details, see Crystal Selection Considerations in the Application Informa-

tion section.

60

XO

Table 1. Signal Descriptions (continued)

Pin

Signal*

Type

Name/Description

* Active-low signals are indicated by “/” at the beginning of signal names, within this document.