SLXT914QC.B3 Intel, SLXT914QC.B3 Datasheet - Page 21

• Manufacturer Part Number: SLXT914QC.B3
• Description: IC QUAD ETHERNET REPEATER 100QFP
• Manufacturer: Intel
• Type: Repeaterr

Specifications of SLXT914QC.B3

• Rohs Status: RoHS non-compliant
• Tx/rx Type: Ethernet
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 180mA
• Mounting Type: Surface Mount
• Package / Case: 100-QFP
• Delay Time: -
• Capacitance - Input: -
• Other names: 831521

2.5.1.1
2.5.1.2
2.5.2
2.5.3
Datasheet
Programmable Internal Squelch Level
The 10BASE-T port receivers have two squelch levels: a normal level or default setting and a
reduced level squelch (-4.5 dB) selected when the ERSQx is set in the Setup register. When used
with Low noise media such as shielded twisted-pair cabling, the reduced squelch level allows
longer loop lengths in the network.
Polarity Detection and Correction
The LXT914 Repeater 10BASE-T ports detect and correct for reversed polarity by monitoring link
pulses and end-of-frame sequences. A reversed polarity condition is declared when the port
receives sixteen or more incorrect link pulses consecutively, or four frames with reversed start-of-
idle sequence. In these cases the receiver reverses the polarity of the signal and thereby corrects for
this failure condition. If the port enters the link fail state and no valid data or link pulses are
received within 96 to 128 ms, the polarity is reset to the default non-flipped condition. (If Link
Integrity Testing is disabled, polarity detection is based only on received data.)
10BASE-T Transmission
Each LXT914 Repeater 10BASE-T port receives NRZ data from the repeater core and passes it
through a Manchester encoder. The encoded data is then transmitted to the twisted-pair network
(the DO circuit). The advanced integrated pulse shaping and filtering network produces the pre-
distorted and pre-filtered output signal to meet the 10BASE-T jitter template. An internal
continuous resistor-capacitor filter is used to remove any high-frequency clocking noise from the
pulse shaping circuitry. Integrated filters simplify the design work required for FCC compliant
EMI performance. During idle periods, the LXT914 Repeater 10BASE-T ports transmit link
integrity test pulses in accordance with the 802.3 10BASE-T standard.
Data packets transmitted by the LXT914 Repeater contain a minimum of 56 preamble bits before
the start of frame delimiter (SFD). In the Asynchronous mode, preamble regeneration takes place
on the transmit side. In the Synchronous mode, the preamble is regenerated on the receive side and
distributed via the IRB. If the total packet is less than 96 bits including the preamble, the
LXT914 Repeater extends the packet length to 96 bits by appending a Jam signal (1010...) at the
end.
10BASE-T Link Integrity Testing
The LXT914 Repeater fully supports the 10BASE-T Link Integrity test function. The link integrity
test determines the status of the receive side twisted-pair cable. Link integrity testing is enabled
unless disabled via the DISLIx bit in the Setup register. When enabled, the receiver recognizes link
integrity pulses transmitted in the absence of data traffic. With no data packets or link integrity
pulses within 100 (±50) ms, the port enters a link fail state and disables its transmitter. The port
remains in the link fail state until it detects three or more data packets or link integrity pulses.
Intel
®
Order Number: 248989, Revision: 003
LXT914 Flexible Quad Ethernet Repeater
Intel
®
LXT914 Flexible Quad Ethernet Repeater
31-Oct-2005
21