CS61574A-75 Cirrus Logic, Inc., CS61574A-75 Datasheet - Page 11

• Manufacturer Part Number: CS61574A-75
• Description: T1-E1 Line Interface Unit for Stratum-4 applications
• Manufacturer: Cirrus Logic, Inc.

Transmitter
The transmitter takes digital T1 or E1 input data
and drives appropriately shaped bipolar pulses
onto a transmission line. The transmit data (TPOS
& TNEG or TDATA) is supplied synchronously
and sampled on the falling edge of the input
clock, TCLK.
Either T1 (DSX-1 or Network Interface) or E1
CCITT G.703 pulse shapes may be selected.
Pulse shaping and signal level are controlled by
"line length select" inputs as shown in Table 3.
DS154F2
RECEIVER/DPM
LEN2 LEN1 LEN0
TRANSMITTER
FUNCTION
0
1
1
1
1
0
0
0
0
CONTROL
1
0
0
1
1
0
0
1
1
Table 3. Line Length Selection
Table 2. Pin Definitions
PIN HARDWARE
1
0
1
0
1
0
1
0
1
11
17
18
18
23
24
25
26
27
28
3
4
6
7
FCC PART 68, OPT. A
RLOOP
MRING
LLOOP
Option Selected
RNEG
TPOS
TNEG
RPOS
TAOS
MTIP
LEN0
LEN1
LEN2
DPM
133-266 FEET
266-399 FEET
399-533 FEET
533-655 FEET
120 (1:1.26)
AT&T CB113
ANSI T1.403
0-133 FEET
-
75 (1:1)
HARDWARE
EXTENDED
RCODE
TCODE
RLOOP
LLOOP
RDATA
MODE
TDATA
LEN0
LEN1
LEN2
TAOS
BPV
PCS
AIS
-
CCITT G.703
Application
(AT&T 600B
Repeater
or 600C)
Interface
Network
DSX-1
ABAM
MRING
RNEG
HOST
TNEG
RPOS
TPOS
SCLK
CLKE
E1
MTIP
DPM
SDO
INT
SDI
CS
-
-0.5
The CS61575 and CS61574A line drivers are de-
signed to drive a 75
For E1 applications, the CS61574A and CS61575
drivers provide 14 dB of return loss during the
transmission of both marks and spaces. This im-
proves signal quality by minimizing reflections
off the transmitter. Similar levels of return loss
are provided for T1 applications.
For T1 DSX-1 applications, line lengths from 0 to
655 feet (as measured from the transmitter to the
DSX-1 cross connect) may be selected. The five
partition arrangement in Table 3 meets ANSI
T1.102 and AT&T CB-119 requirements when
using #22 ABAM cable. A typical output pulse is
shown in Figure 8. These pulse settings can also
be used to meet CCITT pulse shape requirements
for 1.544 MHz operation.
For T1 Network Interface applications, two addi-
tional options are provided. Note that the optimal
pulse width for Part 68 (324 ns) is narrower than
the optimal pulse width for DSX-1 (350 ns). The
CS61575 and CS61574A automatically adjusts
the pulse width based upon the "line length" se-
lection made.
Figure 8. Typical Pulse Shape at DSX-1 Cross Connect
1.0
0.5
0
0
NORMALIZED
AMPLITUDE
250
PULSE SHAPE
OUTPUT
TIME (nanoseconds)
500
equivalent load.
CS61574A CS61575
ANSI TI.102,
AT&T CB 119
SPECIFICATIONS
750
1000
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