
T7296 DS3/STS-1/E3
Integrated Line Transmitter
Data Sheet
February 2000
4
Lucent Technologies Inc.
Pin Information
(continued)
Table 1. Pin Descriptions
(continued)
* If a bipolar violation occurs, RPOS and RNEG can correspond to decoded versions of RPDATA and RNDATA respectively. If DECODIS is high, RPOS and RNEG
always track RPDATA and RNDATA, respectively.
Note: Pins with the I
u
designation have an internal pull-up.
Overview
5-2142(C)r.8
* Shield bead is the FairRite
2643000101 or equivalent.
Output transformer Pulse Engineering
§
PE-65966 (through-hole) or PE-65967 (surface mount) or equivalent.
FairRiteis a registered trademark of FairRite Products Corporation.
§ Pulse Engineeringis a registered trademark of Pulse Engineering, Inc.
Note: Lucent Technologies does not endorse the use of or assume liability for the use of any bead or transformer.
Figure 3. T7296 Application DS3 Mode, Less Than 225 Feet of Cable
Pin
25
Symbol
TXLEV
Type
I
Name/Function
Transmit Level Select.
The output signal amplitude at TTIP and TRING can be varied
by setting this pin high or low. When the cable length is greater than 225 ft., TXLEV
should be set high. When it is below 225 ft., it should be set low. This pin is active only
when the DS3, STS-1/
E3
input (pin 4) is set high (DS3, STS-1 mode).
In-Circuit Testing (Active-Low).
A low at this pin causes all digital and analog outputs
to go into a high-impedance state to allow for in-circuit testing. Internally pulled high.
Receive Positive Data.
NRZ input data to the decoder block. Sampled on the falling
edge of RCLK.
Receive Negative Data.
NRZ input data to the decoder block. Sampled on falling edge
of RCLK.
26
ICT
I
u
27
RPDATA
I
28
RNDATA
I
SHIELD BEAD*
+5 V
T1
728A CABLE
36
36
0.1 μF
0.1 μF
728A CABLE
T7295-6
FROM
SYSTEM
TO
SYSTEM
0.01 μF
R
IN
75
1
2
3
4
5
6
7
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
RNDATA
RPDATA
V
DDA
TTIP
GND
A
TRING
DMO
RNEG
RPOS
RCLK
V
DDD
TNDATA
TPDATA
GND
D
TCLK
8
RLOOP
LLOOP
TAOS
ENCODIS
DECODIS
BPV
RNRZ
MRING
MTIP
RCLKO
TXLEV
ICT
DS3,STS-1/E3