82562GT Datasheet, PDF (21/46 Pages) Intel Corporation – 10/100 Mbps Platform LAN Connect (PLC)

Networking Silicon — 82562GT
5.1.1.4
Transmit Driver
The transmit differential lines are implemented with a digital slope controlled current driver that
meets Twisted Pair Physical Media Device (TP-PMD) specifications. Current is sunk from the
isolation transformer by the transmit differential pins. The conceptual transmit differential
waveform for 100 Mbps is illustrated in Figure 3.
Figure 3. Conceptual Transmit Differential Waveform
5.1.2
5.1.2.1
5.1.2.2
5.1.2.3
The magnetics module external to the 82562GT converts I_TDP and I_TDN to 2.0 V_PP, as required by
the TP-PMD specification. The same magnetics used for 100BASE-TX mode can also work in
10BASE-T mode.
100BASE-TX Receive Blocks
The receive subsection of the 82562GT accepts 100BASE-TX MLT-3 data on the receive
differential pair. Due to the advanced digital signal processing design techniques employed, the
82562GT accurately receives valid data from Category 5 (CAT5) UTP and Type 1 STP cables of
length well in excess of 100 meters.
Adaptive Equalizer
The distorted MLT-3 signal at the end of the wire is restored by the equalizer. The equalizer
performs adaptation based on the shape of the received signal, equalizing the signal to meet
superior data dependent jitter performance.
Receive Clock and Data Recovery
The clock recovery circuit uses advanced digital signal processing technology to compensate for
various signal jitter causes. The circuit recovers the 125 MHz clock and data and presents the data
to the MLT-3 decoder.
MLT-3 Decoder, Descrambler, and Receive Digital Section
The 82562GT first decodes the MLT-3 data, and then the descrambler reproduces the 5B symbols
originated in the transmitter. The descrambling is based on synchronization to the transmission of
the 11-bit Linear Feedback Shift Register (LFSR) during an idle phase. The data is decoded at the
4B/5B decoder. After the 4B symbols are obtained, the 82562GT outputs the receive data to the
CSMA unit.
Datasheet
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