
6
Lucent Technologies Inc.
Data Sheet
March 1997
L7554 Low-Power SLIC
Functional Description
Table 2. Input State Coding
Table 3. Supervision Coding
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.
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
inductance in the V
BAT
 lead could resonate with the V
BAT
 filter capacitor to cause a destructive overvoltage.
BAT
 connection chatters, and 2) 
B0
1
B1
1
B2
1
State/Definition
Powerup, Forward Battery.
PR. On-hook transmission is enabled.
Powerup, Reverse Battery. 
PT. On-hook transmission is enabled.
Ground Start.
 Tip drive amplifier is turned off. The device presents a high-impedance (>100 k
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 k
).
 Normal talk and battery feed state. Pin PT is positive with respect to 
1
1
0
Normal talk and battery feed state. Pin PR is positive with respect to 
0
1
1
) 
0
1
0
0
0
1
0
0
0
Pin NLC
Pin NRDET
Pin RGDET
0 = off-hook
1 = on-hook
0 = ring trip
1 = no ring trip
1 = ring ground
0 = no ring ground
Parameter
Symbol
V
CC
V
BAT
—
—
T
T
stg
R
—
V
PT
, V
V
PT
, V
, I
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
μ
A
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 
Current into Ring Trip Inputs
J
H
PR
μ
s)
PR
I
RTSP
RTSN