10

10

Agere Systems Inc.

Data Sheet, Rev. 3

May 2004

Two-Cable Transceiver/Arbiter Device

FW802B Low-Power PHY IEEE 1394A-2000

37

TPBIAS0

Analog I/O Portn, Twisted-Pair Bias. (Where n refers to the port number). 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. When the FW802B’s 1394 port

pins are not wired to a connector, the unused port pins may be left uncon-

nected. Internal connect-detect circuitry will keep the port in a discon-

nected state.

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 load capacitors and resistor are dependent on the

specifications of the crystal used. It is necessary to add an external series

the Crystal Selection Considerations section in the data sheet. Note that it

is very important to place the crystal as close as possible to the XO and XI

pins, i.e., within 0.5 in./1.27 cm.

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.