SLXT332QE.G2 Cortina Systems Inc, SLXT332QE.G2 Datasheet - Page 19

• Manufacturer Part Number: SLXT332QE.G2
• Manufacturer: Cortina Systems Inc

Specifications of SLXT332QE.G2

• Operating Supply Voltage (typ): 5V
• Screening Level: Industrial
• Mounting: Surface Mount
• Operating Supply Voltage (min): 4.75V
• Operating Supply Voltage (max): 5.25V
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Lead Free Status / RoHS Status: Not Compliant

LXT332
Datasheet
249075, Revision 2.0
26 June 2007
4.2.2
Table 5
4.3
Cortina Systems
1. Line length from LXT332 to DSX
2. Maximum cable loss at 772 kHz
LEN2
0
1
1
1
1
0
0
0
LEN1
1
0
0
1
1
0
0
1
Pulse Shape
The transmitted pulse shape is determined by Line Length equalizer control signals LEN0
through LEN2 as shown in
Host mode the LEN codes are input through the serial interface. Shaped pulses are
applied to the AMI line driver for transmission onto the line at TTIP and TRING. The line
driver provides a constant low output impedance of less than 3 Ω (typical), regardless of
whether it is driving marks or spaces. This well controlled impedance provides excellent
return loss when used with external precision resistors (± 1% accuracy) in series with the
transformer.
transformer data, series resistor (Rt) values, and typical return losses for various LEN
codes. To minimize power consumption the LXT332 can be tied directly to a 1:1.15
transformer without series resistors.
Pulses can be shaped for either 1.544 Mbps or 2.048 Mbps applications. 1.544 Mbps
pulses for DSX-1 applications can be programmed to match line lengths from 0 to 655 feet
of 22 AWG ABAM cable. A combination of 9.1 Ω resistors and a 1:2.3 transformer is
recommended for DSX-1 applications. The LXT332 also matches FCC pulse mask
specifications for CSU applications.
Equalizer Control Inputs
The LXT332 produces 2.048 Mbps pulses for both 75 Ω coaxial (2.37 V) or 120 Ω
shielded (3.0 V) lines through an output transformer with a 1:2 turns ratio. For coaxial
systems, 9.1 Ω series resistors are recommended. For twisted-pair lines, use 15 Ω
resistors.
Driver Failure Monitor
The transceiver incorporates an internal Driver Failure Monitor (DFM) in parallel with TTIP
and TRING. A capacitor, charged via a measure of the driver output current and
discharged by a measure of the maximum allowable current, detects driver failure.
Shorted lines draw excess current, overcharging the capacitor. When the capacitor charge
deviates outside the nominal charge window, a driver failure is reported. In Host mode the
DFM bit is set in the serial word. In Hardware mode the DFM pin goes High. During a long
string of spaces, a short-induced overcharge eventually bleeds off, clearing the DFM flag.
The DFM feature will only detect short circuits when a very short cable is present at the
output. Note that different cable lengths will change the short-circuit current substantially.
®
LXT332 Dual T1/E1 Line Interface Unit with Crystal-less Jitter Attenuation
LEN0
1
0
1
0
1
0
1
0
Table 9
-
1 cross
133 – 266 ft. ABAM
266 – 399 ft. ABAM
399 – 533 ft. ABAM
533 – 655 ft. ABAM
0 – 133 ft. ABAM
Line Length
ITU Recommendation G.703
lists recommended transformer specifications.
-
FCC Part 68, Option A
connect point
Table
1
5. Equalizer codes are hardwired in Hardware mode. In
Cable Loss
0.6 dB
1.2 dB
1.8 dB
2.4 dB
3.0 dB
2
E1 – Twisted
E1 – Coax (75 Ω)
Application
DSX
CSU
-
pair (120 Ω)
-
1
4.3 Driver Failure Monitor
Table 10
lists transmit
1.544 Mbps
2.048 Mbps
1.544 Mbps
Transmit
Rate
Page 19