fw802a ETC-unknow, fw802a Datasheet - Page 11

• Manufacturer Part Number: fw802a
• Description: Low-power Ieee 1394a-2000 Two-cable Transceiver/arbiter Device
• Manufacturer: ETC-unknow

June 2001
Application Information
1394 Application Support Contact Information
E-mail: [e-mail]
Crystal Selection Considerations
The FW802A is designed to use an external 24.576 MHz crystal connected between the XI and XO terminals to
provide the reference for an internal oscillator circuit. IEEE 1394a-2000 standard requires that FW802A have less
than ±100 ppm total variation from the nominal data rate, which is directly influenced by the crystal. To achieve this,
it is recommended that an oscillator with a nominal 50 ppm or less frequency tolerance be used.
The total frequency variation must be kept below ±100 ppm from nominal with some allowance for error introduced
by board and device variations. Trade offs between frequency tolerance and stability may be made as long as the
total frequency variation is less than ±100 ppm.
Agere Systems Inc.
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TPBIAS1
TPA1+
TPA1–
TPB1+
TPB1–
TPBIAS0
TPA0+
TPA0–
TPB0+
TPB0–
220 pF
56 Ω
56 Ω
56 Ω
5 kΩ
56 Ω
TPBIAS1
0.33 µF
(continued)
POWER
Figure 4. Typical Port Termination Network
CABLE
VP
5
3
1
USE SAME PORT TERMINATION NETWORK AS ILLUSTRATED BELOW.
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4
2
VG
IEEE 1394-1995 STANDARD
Two-Cable Transceiver/Arbiter Device
CONNECTOR
5-6930 (F)
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