Dual-Speed Fast Ethernet Transceiver — LXT970A
3.0
3.1
Application Information
Magnetics Information
The LXT970A requires a 1:1 ratio for both the receive and the transmit transformers. Refer to
for magnetics requirements.
A cross-reference list of magnetic manufacturers and part numbers is available in
Application Note
73, Magnetic Manufacturers,
which can be found on the Intel web site (developer.intel.com/design/
network/). Designers must test and evaluate all components for suitability in their applications.
Table 18. Magnetics Requirements
Parameter
Rx and Tx Turns Ratio
Insertion Loss
Primary Inductance
Transformer Isolation
Differential to common mode rejection
–
–
Return Loss
–
Rise Time
2.0
–
–
-15
3.5
dB
ns
60 to 100 MHz
10% to 90%
–
–
-35
-17
dB
dB
60 to 100 MHz
.1 to 60 MHz
Min
–
0.0
350
–
–
Nom
1:1
–
–
2
–
Max
–
1.1
–
–
-40
Units
–
dB
Test Condition
µ
H
kV
dB
.1 to 60 MHz
3.2
Crystal Information
The LXT970A requires a parallel-resonant fundamental-mode crystal that meet specifications as
shown in
XI and XO input capacitance and voltage requirements are provided in
Crystals are available from various manufacturers. Designers should test and validate all crystals
before committing to a specific component. Based on limited evaluation,
provides
suitable crystal component manufacturers.
Table 19. Crystal Requirements
Parameter
Frequency
Frequency Stability
Min
–
–
Nom
25.0
–
Max
–
±100
Units
MHz
ppm
-40 - 85
o
C
Test Condition
1. See
(Clock Characteristics) for additional device specifications.
Table 20. Crystal Component Manufacturers
Component
Crystal
Caliber Electronics
AA18C1-25.000MHz
Manufacturer
Epson America
Part Number
MA-505-25.000M
Datasheet
41
INTEL [ INTEL CORPORATION ]
