lxt971a Intel Corporation, lxt971a Datasheet - Page 48

• Manufacturer Part Number: lxt971a
• Description: 3.3v Dual-speed Fast Ethernet Phy Transceiver
• Manufacturer: Intel Corporation

LXT971A 3.3V Dual-Speed Fast Ethernet Transceiver
4.0
4.1
4.2
48
Table 15. Magnetics Requirements
Table 16. I/O Pin Comparison of NIC and Switch RJ-45 Setups
Application Information
Magnetics Information
The LXT971A requires a 1:1 ratio for both the receive and transmit transformers. The transformer
isolation voltage should be rated at 2 kV to protect the circuitry from static voltages across the
connectors and cables. Refer to
A cross-reference list of magnetic manufacturers and part numbers is available in Magnetic
Manufacturers for Networking Product Applications (document number 248991) and is found on
the Intel web site (www.Intel.com). Before committing to a specific component, contact the
manufacturer for current product specifications and validate the magnetics for the specific
application.
Typical Twisted-Pair Interface
Table 16
typical twisted-pair interface setting.
Figure 22 on page 49
over for a Switch configuration.
the RJ-45 connections configured for a NIC application.
Rx turns ratio
Tx turns ratio
Insertion loss
Primary inductance
Transformer isolation
Differential to common mode rejection
Return Loss
Symbol
TPON
TPOP
TPIP
TPIN
provides a comparison of the RJ-45 connections for NIC and Switch applications in a
Parameter
shows a typical twisted-pair interface with the RJ-45 connections crossed
Switch
1
2
3
6
Table 15
Figure 23 on page 50
RJ-45
Min
350
-16
-10
0.0
40
35
–
–
–
for transformer requirements.
NIC
3
6
1
2
Nom
1 : 1
1 : 1
0.6
1.5
–
–
–
–
–
provides a typical twisted-pair interface with
Max
1.1
–
–
–
–
–
–
–
–
Units
dB
P H
kV
dB
dB
dB
dB
–
–
Rev. Date: August 7, 2002
Test Condition
60 to 100 MHz
Document #: 249414
.1 to 60 MHz
30 MHz
80 MHz
Revision #: 002
Datasheet
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