Data Sheet
October 1997
L7591 Subscriber Line Interface Circuit Protector
Features
s
Description
The L7591 Subscriber Line Interface Circuit (SLIC)
Protector is designed to protect line-feed circuitry
from fault-induced lightning and power-cross surge
pulses. If a fault current forces TIP and/or RING to a
more negative voltage than V
S
, current is conducted
through the trip circuit. When the specified trip cur-
rent level is reached, transistors PNPN1 and/or
PNPN2 will turn on and "crowbar" the majority of the
current to ground. If similar pulses force TIP and/or
RING to a more positive state than ground, diodes
D1 and/or D2 will conduct the pulse to ground. The
L7591 SLIC Protector is available in an 8-pin, plastic
DIP (L7591AB) and in an 8-pin, plastic SONB pack-
age (L7591AS).
Shunts lightning pulses to ground
— Positive or negative 30 A, 10 x 1000
µs
— Positive or negative 40 A, 5 x 320
µs
— Positive or negative 80 A, 2 x 10
µs
Power-cross protection
— 3.5 A
PEAK
, 50 Hz to 60 Hz, 1 s
— 5.0 A
PEAK
, 50 Hz to 60 Hz, 10 ms
Gate trigger current, 15 mA max
Up to –80 V capability
Holding current, 150 mA min
s
s
s
s
Pin Information
Table 1. Pin Description
(Applies to DIP and SONB packages)
Pin
1
2
3
4
5
6
7
8
Symbol
TIP
V
S
—
RING
PR
GND
GND
PT
Name/Function
Tip signal from customer.
Supply voltage to gate
(–20 V to –80 V).
Test Point, do not use.
Ring signal from customer.
Protected ring signal to line-feed-
circuitry.
Device ground/fault current
return.
Device ground/fault current
return.
Protected tip signal to line-feed
circuitry.
V
S
2
TIP
1
TRIP
CIRCUIT
PNPN1
7 GND
D1
8 PT
TEST
POINT
3
PNPN2
TRIP
CIRCUIT
D2
6 GND
RING
4
5 PR
12-1590 (C)
Figure 1. Functional and Pin Diagram
Note: Pins 1 and 4 must always be connected to the protection
resistors shown in Figures 4 and 5 (Line Feed Circuitry). The
SLIC can be connected either to the protected outputs (pins
5 and 8) or to the inputs (pins 1 and 4).
L7591 Subscriber Line Interface Circuit Protector
Data Sheet
October 1997
Absolute Maximum Ratings
(At 25
°C)
Stresses in excess of the Absolute Maximum Ratings can cause permanent damage to the device. These are
absolute 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 the device reliability.
Parameter
Ambient Operating Temperature
Storage Temperature Range
Pin Soldering Temperature (t = 15 s max)
Supply Voltage
Peak Pulse Current: * (See Figure 2.)
10 x 1000
µs
5 x 320
µs
2 x 10
µs
Nonrepetitive Peak ON-state Current:
t = 1 s, f = 50 Hz to 60 Hz
t = 10 ms, f = 50 Hz to 60 Hz
Maximum Gate Current (Half Sine Wave 10 ms)
Maximum Voltage:
TIP or RING to Gnd
V
S
to Gnd
*Pulse Waveform Data:
10 x 1000
µs
5 x 320
µs
2 x 10
µs
tr = 10
µs
tr = 5
µs
tr = 2
µs
tp = 1000
µs
tp = 320
µs
tp = 10
µs
Symbol
T
A
T
stg
—
V
S
—
—
—
—
—
—
—
—
Value
–40 to +85
–40 to +125
300
–83
30
40
80
3.5
5
2
–100
–80
Unit
°C
°C
°C
V
A
A
A
A
A
A
V
V
% IPP
100
50
0
tr
tp
t
Figure 2. Pulse Waveform
2
Lucent Technologies Inc.
Data Sheet
October 1997
L7591 Subscriber Line Interface Circuit Protector
Electrical Specifications
(T
A
= 25
°C)
The minimum and/or maximum limits specified for the parameters are based on the absolute system. The alge-
braic sign only applies to the direction of the parameter. These requirements apply to either the TIP or RING termi-
nal; however, the device is capable of simultaneous Tip and Ring surges and continuous current, as noted below in
Tip and Ring leads. See Figure 3 and Table 5 for symbol and test condition definition.
Table 2. Electrical Characteristics D1 and D2
Characteristic
Forward Voltage
Peak Forward Voltage
Symbol
V
F
V
FP
Test Conditions
I
P
= 5 A, t
P
= 1 ms
I
PP
= 30 A, 10 x 1000
µs
Min
—
—
Typ
1.6
5.2
Max
3
15
Unit
V
V
Table 3. Electrical Characteristics, PNPN Circuitry
Characteristic
Gate Trigger Current
Holding Current
Trip Voltage
Dynamic Trip Voltage
Reverse Leakage Current:
V
S
to Tip or Ring
T
A
= 25
°C
T
A
= 70
°C
dv/dt Sensitivity
On-state Voltage:
I
T
= 0.5 A
I
T
= 3.0 A
Symbol
I
GT
I
H
V
T
V
SGL
I
RG
—
—
—
V
ON
—
—
Test Conditions
V
S
= 48 V
t
P
= 10 ms, V
S
= 48 V
dc
I
PP
= 30 A, V
S
= –48 V,
10 x 1000
µs
V
S
= –75 V
—
—
Tip or Ring Lead
t
P
= 1 ms
—
—
Min
0.2
–150
—
—
Typ
—
–250
V
S
–2.0
–51
Max
15
—
V
S
–2.8
–63
Unit
mA
mA
V
V
—
—
±1000
—
—
0.12
—
—
–1.3
–2.3
5
50
—
—
—
µA
µA
V/µs
V
V
Table 4. Electrical Characteristics, Diode and PNPN Circuitry
Characteristic
Reverse Leakage Current:
(Gate Open)
T
A
= 25
°C
T
A
= 70
°C
Off-state Capacitance:
V
R
= –3 V
V
R
= –48 V
Symbol
I
R
—
—
C
off
—
—
Test Conditions
V
R
= –85 V
—
—
f = 1 MHz
—
—
—
—
—
—
0.14
—
50
40
5
50
—
—
µA
µA
pF
pF
Min
Typ
Max
Unit
Lucent Technologies Inc.
3
L7591 Subscriber Line Interface Circuit Protector
Data Sheet
October 1997
Characteristic Curves
I
I
P
I
PP
V
ON
V
SGL
V
R
I
R
I
H
V
F
V
I
T
I
PP
Figure 3. Typical Trip Characteristics of the SLIC Protector
Table 5. Symbols Definition
Symbol
I
H
I
GT
I
P
I
PP
I
RG
I
T
I
R
V
F
V
FP
V
T
V
SGL
V
ON
V
R
C
off
Parameter
PNPN holding current
Gate trigger current out of pin V
S
Pulse current
Peak pulse current
Reverse leakage current V
S
to Tip or Ring
Tip or Ring current when PNPN is on
Reverse leakage current, Tip or Ring to Ground
Forward voltage, Tip or Ring to Ground
Peak forward voltage, Tip or Ring to Ground
Trip voltage, Tip or Ring to V
S
Dynamic trip voltage, Tip or Ring to V
S
PNPN on voltage at I
T
Tip or Ring voltage when PNPN is off
Off-state capacitance, Tip or Ring to Ground
4
Lucent Technologies Inc.
Data Sheet
October 1997
L7591 Subscriber Line Interface Circuit Protector
Applications
TIP
R
PT
TRIP
CIRCUIT
2
–V
S
7
1
8
PROTECTED
TIP
3
TRIP
CIRCUIT
R
PR
RING
4
6
5
PROTECTED
RING
12-1632 (C)
R
PT
and R
PR
must be properly selected for proper operation and/or response.
Figure 4. Standard Configuration
I
P
1
TRIP
CIRCUIT
2
–48 V
7
8
V
MEAS
3
TRIP
CIRCUIT
4
I
P
6
V
MEAS
5
12-1596 (C)
Figure 5. Test Circuit
TIP
PTC
CARBON
BLOCK
RELAYS
1
8
6
7
L7591AB
SLIC
PROTECTOR
2
BATTERY
FEED*
CARBON
BLOCK
PTC
RING
4
5
V
S
(–20 V TO –80 V)
12-1598 (C)
*An example device is Lucent Technologies Microelectronics Group’s LB1276 High Balance SLIC.
Figure 6. Fully Protected Electronic TIP-RING Interface
(Not all devices needed in all applications)
Lucent Technologies Inc.
5
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