ICS1893Y-10 Datasheet, PDF (51/150 Pages) –

ICS1893Y-10 - Release
Chapter 6 Functional Blocks
6.4.4 100Base-TX Operation: Adaptive Equalizer
The ICS1893Y-10 has a TP-PMD sublayer that uses adaptive equalization circuitry to compensate for
signal amplitude and phase distortion incurred from the transmission medium. At a data rate of 100 Mbps,
the transmission medium (that is, the cable) introduces significant signal distortion because of
high-frequency attenuation and phase shift. The high-frequency loss occurs primarily because of the cable
skin effect that causes the conductor resistance to rise as the square of the frequency rises.
The ICS1893Y-10 has an adaptive equalizer that accurately compensates for these losses in shielded
twisted-pair (STP) and unshielded twisted-pair (UTP) cables. The DSP-based adaptive equalizer uses a
technique that compensates for a wide range of cable lengths. The optimizing parameter for the
equalization process is the overall bit error rate of the ICS1893Y-10. This technique closes the loop on the
entire data reception process and provides a very high overall reliability.
6.4.5 100Base-TX Operation: Twisted-Pair Transmitter
The ICS1893Y-10 uses the same Twisted-Pair Transmit pins (TP_TXP and TP_TXN) for both 10Base-T
and 100Base-TX operations. Each twisted-pair transmitter module is a current-driven, differential driver
that can supply either of the following:
• A two-level 10Base-T (that is, Manchester-encoded) signal
• A three-level 100Base-TX (that is, MLT-3 encoded) signal
The ICS1893Y-10 interfaces with the medium through an isolation transformer (sometimes referred to as a
magnetic module). The ICS1893Y-10’s transmitter uses wave-shaping techniques to control the output
signal rise and fall times (thereby eliminating the need for external filters) and interfaces directly to the
isolation transformer.
Note:
1. In reference to the ICS1893Y-10, the term ‘Twisted-Pair Transmitter’ refers to the set of Twisted-Pair
Transmit output pins (TP_TXP and TP_TXN).
2. For information on the 10Base-T Twisted-Pair Transmitter, see Section 6.5.11, “10Base-T Operation:
Twisted-Pair Transmitter”.
6.4.6 100Base-TX Operation: Twisted-Pair Receiver
The ICS1893Y-10 uses the same Twisted-Pair Receive pins (TP_RXP and TP_RXN) for both 10Base-T
and 100Base-TX operations. The internal twisted-pair receiver modules interface with the medium through
an isolation transformer. The 100Base-TX receiver module accepts and processes a differential three-level
100Base-TX (that is, MLT-3 encoded) signal from the isolation transformer. (In contrast, the 10Base-T
receiver module accepts and processes a differential two-level, Manchester- encoded, 10Base-T signal
from the isolation transformer).
Note:
1. In reference to the ICS1893Y-10, the term ‘Twisted-Pair Receiver’ refers to the set of Twisted-Pair
Receive output pins (TP_RXP and TP_RXN).
2. For information on the 10Base-T Twisted-Pair Receiver, see Section 6.5.12, “10Base-T Operation:
Twisted-Pair Receiver”.
ICS1893Y-10 Rev F 1/20/04
Copyright © 2004, Integrated Circuit Systems, Inc.
All rights reserved.
51
January, 2004