L7554 Low-Power SLIC
Data Sheet
March 1997
Functional Description
Table 2. Input State Coding
B0
1
1
0
B1
1
1
1
B2
1
0
1
State/Definition
Powerup, Forward Battery.
Normal talk and battery feed state. Pin PT is positive with respect to
PR. On-hook transmission is enabled.
Powerup, Reverse Battery.
Normal talk and battery feed state. Pin PR is positive with respect to
PT. On-hook transmission is enabled.
Ground Start.
Tip drive amplifier is turned off. The device presents a high-impedance (>100 kΩ)
to the PT pin and a current-limited battery to the PR pin. Output pin RGDET indicates current flow-
ing in the ring lead.
Low-Power Scan, Reverse Battery.
Except for off-hook supervision, all circuits are shut down to
conserve power. Pin PR is positive with respect to PT. On-hook transmission is disabled.
Low-Power Scan, Forward Battery.
Except for off-hook supervision, all circuits are shut down to
conserve power. Pin PT is positive with respect to PR. On-hook transmission is disabled.
Disconnect.
The Tip and Ring amplifiers are turned off and the SLIC goes to a high-impedance
state (>100 kΩ).
0
0
0
1
0
0
0
1
0
Table 3. Supervision Coding
Pin NLC
0 = off-hook
1 = on-hook
Pin NRDET
0 = ring trip
1 = no ring trip
Pin RGDET
1 = ring ground
0 = no ring ground
Absolute Maximum Ratings
(T
A
= 25
°C)
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are abso-
lute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess
of those given in the operational sections of the data sheet. Exposure to absolute maximum ratings for extended
periods can adversely affect device reliability.
Parameter
5 V Power Supply
Battery (Talking) Supply
Logic Input Voltage
Analog Input Voltage
Maximum Junction Temperature
Storage Temperature Range
Relative Humidity Range
Ground Potential Difference (BGND to AGND)
PT or PR Fault Voltage (dc)
PT or PR Fault Voltage (10 x 1000
µs)
Current into Ring Trip Inputs
Symbol
V
CC
V
BAT
—
—
T
J
T
stg
R
H
—
V
PT
, V
PR
V
PT
, V
PR
I
RTSP
, I
RTSN
Value
7.0
–75
–0.5 to +7.0
–7.0 to +7.0
165
–40 to +125
5 to 95
±3
(V
BAT
– 5) to +3
(V
BAT
– 15) to +15
±240
Unit
V
V
V
V
°C
°C
%
V
V
V
µA
Note: The IC can be damaged unless all ground connections are applied before, and removed after, all other connections. Furthermore, when
powering the device, the user must guarantee that no external potential creates a voltage on any pin of the device that exceeds the
device ratings. Some of the known examples of conditions that cause such potentials during powerup are the following: 1) an inductor
connected to Tip and Ring can force an overvoltage on V
BAT
through the protection devices if the V
BAT
connection chatters, and 2)
inductance in the V
BAT
lead could resonate with the V
BAT
filter capacitor to cause a destructive overvoltage.
6
Lucent Technologies Inc.
AGERE [ AGERE SYSTEMS ]
