SLXT970AQC.B11-831643 Cortina Systems Inc, SLXT970AQC.B11-831643 Datasheet - Page 39

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SLXT970AQC.B11-831643

Manufacturer Part Number
SLXT970AQC.B11-831643
Description
Manufacturer
Cortina Systems Inc
Datasheet

Specifications of SLXT970AQC.B11-831643

Number Of Receivers
1
Data Rate
10/100Mbps
Operating Supply Voltage (typ)
5V
Operating Temperature Classification
Commercial
Operating Supply Voltage (max)
5.25V
Operating Supply Voltage (min)
4.75V
Mounting
Surface Mount
Pin Count
64
Operating Temperature (max)
70C
Operating Temperature (min)
0C
Lead Free Status / RoHS Status
Not Compliant
2.8.2.3
2.8.3
2.8.3.1
2.8.3.2
2.8.3.3
2.8.4
Datasheet
Carrier Sense (CRS)
For 100TX and 100FX links, a start-of-stream delimiter or /J/K symbol pair causes assertion of
carrier sense (CRS). An end-of-stream delimiter, or /T/R symbol pair causes deassertion of CRS.
The PMA layer also de-asserts CRS if IDLE symbols are received without /T/R, however, in this
case RX_ER asserts for one clock cycle when CRS is de-asserted.
For 10T links, CRS assertion is based on reception of valid preamble, and de-assertion on reception
of an end-of-frame (EOF) marker.
The PMA layer in the LXT970A Transceiver does not support the optional Far-End-Fault function.
Twisted-Pair PMD Layer
The twisted-pair Physical Medium Dependent (PMD) layer provides the signal scrambling and
descrambling, line coding and decoding (MLT-3 for 100TX, Manchester for 10T), as well as
receiving, polarity correction, and baseline wander correction functions.
Scrambler/Descrambler (100TX Only)
The scrambler spreads the signal power spectrum and reduces EMI and baseline wander.
Scrambling is done with an 11-bit, non-data-dependent polynomial. The receiver automatically
decodes the polynomial whenever IDLE symbols are received.
The LXT970A Transceiver provides a scrambler-bypass mode for testing purposes. Bypassing the
scrambler causes the PCS-layer encoder to be bypassed as well, and the MII to operate in 5B mode.
Baseline Wander Correction
(100TX Only)
The LXT970A Transceiver provides a baseline wander correction function that makes the device
robust under all network operating conditions. The MLT3 coding scheme used in 100BASE-TX is
by definition “unbalanced”, which means the average DC value of the signal voltage can “wander”
significantly over short time intervals (tenths of seconds). In less robust PHY devices, this wander
can cause receiver errors, particularly at long line lengths (100 meters). The exact characteristics of
the wander are completely data dependent. The LXT970A Transceiver baseline wander correction
circuitry allows error-free data recovery, even at long line lengths.
Polarity Correction
The LXT970A Transceiver automatically detects and corrects for the condition where the receive
signal (TPIP/N) is inverted. Reversed polarity is detected if eight inverted link pulses, or four
inverted end-of-frame markers, are received consecutively. If link pulses or data are not received
for 96-128 ms, the polarity state is reset to a non-inverted state.
Fiber PMD Layer
The LXT970A Transceiver provides a pseudo-ECL interface for connection to an external fiber
optic transceiver. (The external transceiver provides the PMD function for fiber media.) The
LXT970A Transceiver uses an NRZI format for the fiber interface. The fiber interface operates at
Intel
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LXT970A Dual-Speed Fast Ethernet Transceiver
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