LXT971A 3.3V Dual-Speed Fast Ethernet Transceiver
Figure 23. Typical Twisted-Pair Interface - NIC
RJ-45
50
50
Ω
50
50
Ω
Ω
270 pF 5%
TPFIN
8
7
6
5
4
3
2
1
50Ω 1%
1:1
1:1
50
50
Ω
Ω
0.01 µF
50Ω 1%
3
Ω
TPFIP
270 pF 5%
TPFON
LXT971A
2
0.1µF
4
TPFOP
1
* = 0.001 µF / 2.0 kV
*
*
VCCA
GND
.01µF
0.1µF
SD/TP
1. Center-tap current may be supplied from 3.3 V VCCA as shown. Additional power savings may
be realized by supplying the center-tap from a 2.5 V current source. A separate ferrite bead
(rated at 50 mA) should be used to supply center-tap current.
2. The 100 Ω transmit load termination resistor typically required is integrated in the LXT971A.
3. Magnetics without a receive pair center-tap do not require a 2 kV termination.
4. RJ-45 connections shown for standard NIC. TX/RX crossover may be required for repeater and
switch applications.
50
Datasheet
Document #: 249414
Revision #: 002
Rev. Date: August 7, 2002
INTEL [ INTEL ]
