L-ET1011C2-CI-D LSI, L-ET1011C2-CI-D Datasheet - Page 7

• Manufacturer Part Number: L-ET1011C2-CI-D
• Manufacturer: LSI

Specifications of L-ET1011C2-CI-D

• Number Of Receivers: 1
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Lead Free Status / Rohs Status: Compliant

September 2007
Functional Description
Adaptive Fractionally Spaced Equalizer
The ET1011C’s unique oversampling architecture employs
an FSE in place of the traditional FFE structure. This results
in robust equalization of the communications channel, which
translates to superior bit error rate (BER) performance over
the widest variety of worst-case cabling scenarios. The all-
digital equalizer automatically adapts to changing condi-
tions.
Echo and Crosstalk Cancellers
Since the four twisted pairs are bundled together and not
insulated from each other in Gigabit Ethernet, each of the
transmitted signals is coupled onto the three other cables and
is seen at the receiver as near-end crosstalk (NEXT). A
hybrid circuit is used to transmit and receive simultaneously
on each pair. If the transmitter is not perfectly matched to the
line, a signal component will be reflected back as an echo.
Reflections can also occur at other connectors or cable
imperfections. The ET1011C cancels echo and NEXT by
subtracting an estimate of these signals from the equalizer
output.
Baseline Wander Correction
A known issue for 1000Base-T and 100Base-TX is that the
transformer attenuates at low frequencies. As a result, when
a large number of symbols of the same sign are transmitted
consecutively, the signal at the receiver gradually dies away.
This effect is called baseline wander. By employing a circuit
that continuously monitors and compensates for this effect,
the probability of encountering a receive symbol error is
reduced.
LSI Corporation
(continued)
Autonegotiation
Autonegotiation is implemented in accordance with IEEE
802.3. The device supports 10Base-T, 100Base-TX, and
1000Base-T and can autonegotiate between them in either
half- or full-duplex mode. It can also parallel detect 10Base-
T or 100Base-TX. If autonegotiation is disabled, a 10Base-T
or 100Base-TX link can be manually selected via the IEEE
MII registers.
Pair Skew Correction
In Gigabit Ethernet, pair skew (timing differences between
pairs of cable) can result from differences in length or manu-
facturing variations between the four individual twisted-pair
cables. The ET1011C automatically corrects for both integer
and fractional symbol timing differences between pairs.
Automatic MDI Crossover
During autonegotiation, the ET1011C automatically detects
and sets the required MDI configuration so that the remote
transmitter is connected to the local receiver and vice versa.
This eliminates the need for crossover cables or crosswired
(MDIX) ports. If the remote device also implements auto-
matic MDI crossover, and/or the crossover is implemented in
the cable, the crossover algorithm ensures that only one ele-
ment implements the required crossover.
Polarity Inversion Correction
In addition to automatic MDI crossover that is necessary for
autonegotiation, 10Base-T, and 100Base-TX operation, the
ET1011C automatically corrects crossover of the additional
two pairs used in 1000Base-T. Polarity inversion on all pairs
is also corrected. Both of these effects may arise if the
cabling has been incorrectly wired.
Carrier Sense
Only)
The carrier sense signal (CRS) of the MAC interface is
asserted by the ET1011C whenever the receive medium is
nonidle. In half-duplex mode, CRS may also be asserted
when the transmit medium is nonidle. The CRS may be
enabled on transmit in half-duplex mode by writing to the
PHY configuration register, address 22, bit 15.
(128-Pin TQFP and 84-Pin MLCC
Gigabit Ethernet Transceiver
7