lxt972a Intel Corporation, lxt972a Datasheet - Page 40

• Manufacturer Part Number: lxt972a
• Description: 3.3v Dual-speed Fast Ethernet Transceiver Datasheet
• Manufacturer: Intel Corporation

LXT972A — 3.3V Dual-Speed Fast Ethernet Transceiver Datasheet
4.0
4.1
4.2
40
Rx turns ratio
Tx turns ratio
Insertion loss
Primary inductance
Transformer isolation
Differential to common mode rejection
Return Loss
Table 14. Magnetics Requirements
Table 15. RJ-45 Pin Comparison of NIC and Switch Twisted-Pair Interfaces
Parameter
Application Information
Magnetics Information
The LXT972A requires a 1:1 ratio for both the receive and transmit transformers. The transformer
isolation voltage should be rated at 2kV 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 Application Note
073, Magnetic Manufacturers, which can be found on the Intel web site (developer.intel.com/
design/network/). Before committing to a specific component, designers should contact the
manufacturer for current product specifications, and validate the magnetics for the specific
application.
Typical Twisted-Pair Interface
Table 15
typical twisted-pair interface setting.
Figure 21 on page 41
over for a switch configuration.
the RJ-45 connections configured for a NIC application.
Symbol
TPOP
TPON
TPIP
TPIN
provides a comparison of the RJ-45 connections for NIC and switch applications in a
shows a typical twisted-pair interface with the RJ-45 connections crossed
Switch
Min
350
-16
-10
0.0
40
35
1
2
3
6
–
–
–
Table 14
Figure 22 on page 42
RJ-45
Nom
1 : 1
1 : 1
0.6
1.5
–
–
–
–
–
for transformer requirements.
NIC
3
6
1
2
Max
1.1
–
–
–
–
–
–
–
–
provides a typical twisted-pair interface with
Units
dB
kV
dB
dB
dB
dB
–
–
H
.1 to 60 MHz
60 to 100 MHz
30 MHz
80 MHz
Test Condition
Datasheet