CS61535A Cirrus Logic, Inc., CS61535A Datasheet - Page 12

• Manufacturer Part Number: CS61535A
• Description: T1-E1 Line Interface Unit for PCM applications
• Manufacturer: Cirrus Logic, Inc.

CS61535A line driver is designed to drive a 75
equivalent load.
For T1 DSX-1 applications, line lengths from 0 to
655 feet (as measured from the transmitter to the
DSX-1 cross connect) are selectable. The five
partition arrangement meets ANSI T1.102-1993
requirements when using 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, additional
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
CS61535A automatically adjusts the pulse width
based upon the "line length " selection made.
The E1 G.703 pulse shape is supported with line
length selection LEN2/1/0=0/0/0. The pulse
12
LEN2 LEN1 LEN0
0
1
1
1
1
0
0
0
0
1
0
0
1
1
0
0
1
1
Nominal peak voltage of a mark (pulse)
Peak voltage of a space (no pulse)
Nominal pulse width
Ratio of the amplitudes of positive and negative
pulses at the center of the pulse interval
Ratio of the widths of positive and negative
pulses at the nominal half amplitude
* When configured with a 0.47 F nonpolarized capacitor in series with the TX transformer
Table 3. Line Length Selection
primary as shown in Figures A1, A2 and A3.
1
0
1
0
1
1
0
0
1
FCC Part 68, Option A
OPTION SELECTED
(CS61535A only)
133-266 FEET
266-399 FEET
399-533 FEET
533-655 FEET
CCITT G.703
AT&T CB113
ANSI T1.403
0-133 FEET
Table 4. CCITT G.703 Specifications
CSU NETWORK
APPLICATION
2.048 MHz E1
INTERFACE
(AT&T 600B
REPEATER
or 600C)
DSX-1
ABAM
For c o axial cab le ,
75
transformer specified
in Application Section.
width will meet the G.703 pulse shape template
shown in Figure 9, and specified in Table 4.
For E1 applications, the CS61535A driver pro-
vides 14 dB of return loss during the transmission
of both marks and spaces. This improves signal
quality by minimizing reflections off the trans-
mitter. Similar levels of return loss are provided
for T1 applications.
The CS61535A transmitter will detect a failed
TCLK, and will force the TTIP and TRING out-
puts low.
-0.5
Figure 8. Typical Pulse Shape at DSX-1 Cross Connect
1.0
0.5
0
0
0 0.237 V
NORMALIZED
AMPLITUDE
2.37 V
loa d
250
0.95 to 1.05*
0.95 to 1.05*
a nd
PULSE SHAPE
244 ns
CS61535A
OUTPUT
TIME (nanoseconds)
500
For shielded twisted
pair, 120
transformer specified
in Application Section.
0 0.30 V
3 V
AT&T CB 119
SPECIFICATION
750
load and
CS61535A
1000
DS40F2