Agere L7582 Tip ring access switch Datasheet

Data Sheet
November 1999
L7582 Tip Ring Access Switch
Features
■
Small size/surface-mount packaging
■
Monolithic IC reliability
■
Low impulse noise
■
Make-before-break, break-before-make operation
■
Clean, bounce-free switching
■
Low, matched ON-resistance
■
Built-in current limiting, thermal shutdown, and
SLIC protection
■
5 V only operation, very low power consumption
■
Battery monitor, all OFF state upon loss of battery
■
No EMI
■
Latched logic level inputs, no drive circuitry
■
Only one external protector required
Applications
■
Central office
■
DLC
■
PBX
■
DAML
■
HFC/FITL
Description
The L7582 Tip Ring Access Switch is a monolithic
solid-state device that provides the switching
functionality of a 2 form C switch.
The L7582 is designed to provide power ringing
access to tip and ring in central office, digital loop
carrier, private branch exchange, digitally added
main line, and hybrid fiber coax/fiber-in-the-loop ana-
log line card applications. An additional pair of solidstate contacts provides access to the telephone loop
for line test access or message waiting in the PBX
application.
The L7582 has four states: the idle talk state (line
break switches closed, ringing and loop access
switches open), the power ringing state (ringing
access switches closed, line break and loop access
switches open), loop access state (loop access
switches closed, line break and ringing access
switches open), and an all OFF state.
The L7582 offers break-before-make or make-beforebreak switching, with simple logic level input control.
Because of the solid-state construction, voltage transients generated when switching into an inductive
ringing load during ring cadence or ring trip are minimized, possibly eliminating the need for external zero
cross switching circuitry. State control is via logic
level inputs so no additional driver circuitry is
required.
The line break switch is a linear switch that has
exceptionally low ON-resistance and an excellent
ON-resistance matching characteristic. The ringing
access switch has a breakdown voltage rating
>480 V which is sufficiently high, with proper protection, to prevent breakdown in the presence of a transient fault condition (i.e., passing the transient on to
the ringing generator).
Incorporated into the L7582Axx is a diode bridge/
SCR clamping circuit, current-limiting circuitry, and a
thermal shutdown mechanism to provide protection
to the SLIC device and subsequent circuitry during
fault conditions (see Figure 1). Positive and negative
lightning is reduced by the current-limiting circuitry
and steered to ground via diodes and the integrated
SCR. Power cross is also reduced by the currentlimiting and thermal shutdown circuits.
Data Sheet
November 1999
L7582 Tip Ring Access Switch
The L7582Bxx version provides only an integrated
diode bridge along with current limiting and thermal
shutdown as shown in Figure 2. This will cause positive
faults to be directed to ground and negative faults to
battery. In either polarity, faults are reduced by the current-limit and/or thermal shutdown mechanisms.
To protect the L7582 from an overvoltage fault condition, use of a secondary protector is required. The secondary protector must limit the voltage seen at the tip/
ring terminals to prevent the breakdown voltage of the
switches from being exceeded. To minimize stress on
the solid-state contacts, use of a foldback- or crowbartype secondary protector is recommended. With proper
choice of secondary protection, a line card using the
L7582 will meet all relevant ITU-T, LSSGR, FCC, or
UL* protection requirements.
The L7582 operates from a 5 V supply only. This
gives the device extremely low idle and active power
dissipation and allows use with virtually any range of
battery voltage. This makes the L7582 especially
appropriate for remote power applications such as
DAML or FOC/FITL or other Bellcore TA 909 applications where power dissipation is particularly critical.
Pin Information
FGND
1
TBAT
2
TLINE
TRINGING
SCR
AND
TRIP
CKT
16 VBAT
15 RBAT
SW1
SW2
SW3
SW4
SW5
SW6
14 RLINE
3
13 RRINGING
4
TACCESS
5
12 RACCESS
VDD
6
11 LATCH
TSD
7
DGND
8
CONTROL
LOGIC
Description (continued)
10 INRING
9
INACCESS
12-2306.i (F)
Note: Shown with A version protection. The 16-pin SOG is available
with either A or B version protection.
Figure 1. 16-Pin, Plastic SOG
A battery voltage is also used by the L7582, only as a
reference for the integrated protection circuit. The
L7582 will enter an all OFF state upon loss of battery.
The L7582 device is packaged in a 16-pin, plastic DIP
package (L7582AC/BC) and a 16-pin, plastic SOG
package (L7582AAE/BAE). The L7582AAE/BAE are
pin compatible with the L7542AAE/BAE.
*UL is a registered trademark of Underwriters Laboratories, Inc.
FGND
1
TBAT
2
TLINE
TRINGING
16 VBAT
15 RBAT
SW1
SW2
SW3
SW4
SW5
SW6
14 RLINE
3
13 RRINGING
4
TACCESS
5
12 RACCESS
VDD
6
11 LATCH
TSD
7
DGND
8
CONTROL
LOGIC
During power ringing, to turn on and maintain the ON
state, the ring access switch will draw a nominal 2 mA
or 4 mA from the ring generator.
10 INRING
9
INACCESS
12-2306.c (F)
Note: Shown with B version protection. The 16-pin DIP is available
with either A or B version protection.
Figure 2. 16-Pin, Plastic DIP
2
Lucent Technologies Inc.
Data Sheet
November 1999
L7582 Tip Ring Access Switch
Pin Information (continued)
Table 1. Pin Descriptions
DIP SOG Symbol
Description
1
1
FGND Fault ground.
2
3
4
2
3
4
TBAT
TLINE
TRINGING
5
6
5
6
TACCESS
VDD
7
7
TSD
8
8
DGND
DIP
16
SOG
16
Symbol
Description
VBAT
Battery voltage. Used as a reference for protection circuit.
RBAT
Connect to RING on SLIC side.
R LINE Connect to RING on line side.
RRINGING Connect to ringing generator.
Connect to TIP on SLIC side.
15
Connect to TIP on line side.
14
Connect to return ground for ring- 13
ing generator.
Test access.
12
5 V supply.
11
15
14
13
10
10
RACCESS Test access.
LATCH Data latch control, active-high,
transparent low.
INRING Logic level input switch control.
9
9
INACCESS Logic level input switch control.
Temperature shutdown pin. Can
be used as a logic level input or
output. See Table 13, Truth Table,
and the Switching Behavior section of this data sheet for input pin
description. As an output, will
read 5 V when device is in its
operational mode and 0 V in the
thermal shutdown mode. To disable the thermal shutdown mechanism, tie this pin to 5 V (not
recommended).
Digital ground.
12
11
Absolute Maximum Ratings
Handling Precautions
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 device reliability.
Although protection circuitry has been designed into
this device, proper precautions should be taken to
avoid exposure to electrostatic discharge (ESD) during
handling and mounting. Lucent Technologies Microelectronics Group employs a human-body model
(HBM) and a charged-device model (CDM) for ESDsusceptibility testing and protection design evaluation.
ESD voltage thresholds are dependent on the circuit
parameters used to define the model. No industry-wide
standard has been adopted for CDM. However, a standard HBM (resistance = 1500 Ω, capacitance = 100 pF)
is widely used and therefore can be used for comparison purposes. The HBM ESD threshold presented
here was obtained by using these circuit parameters.
Table 2. Absolute Maximum Ratings Parameters
Parameter
Operating Temperature Range
Storage Temperature Range
Relative Humidity Range
Pin Soldering Temperature (t =
10 s max)
5 V Power Supply
Battery Supply
Logic Input Voltage
Input-to-output Isolation
Pole-to-pole Isolation
Lucent Technologies Inc.
Min
–40
–40
5
—
Max
110
150
95
260
Unit
°C
°C
%
°C
—
—
—
—
—
7
–85
7
330
330
V
V
V
V
V
Table 3. HBM ESD Threshold Voltage
Device
L7582
Rating
1000 V
3
Data Sheet
November 1999
L7582 Tip Ring Access Switch
Electrical Characteristics
TA = –40 °C to +85 °C, unless otherwise specified.
Minimum and maximum values are testing requirements. Typical values are characteristics of the device and are
the result of engineering evaluations. Typical values are for information purposes only and are not part of the testing requirements.
Table 4. Power Supply Specifications
Supply
VDD
VBAT*
Min
4.5
–19
Typ
5
—
Max
5.5
–72
Unit
V
V
* VBAT is used only as a reference for internal protection circuitry. If VBAT rises above –10 V, the device will enter an all OFF state and will remain
in the all OFF state until the battery voltage drops below –15 V.
Table 5. Break Switches, 1 and 2
Parameter
OFF-state Leakage
Current:
+25 °C
+85 °C
–40 °C
ON-resistance
(SW1, SW2):
+25 °C
+85 °C
–40 °C
ON-resistance Match
ON-state Voltage*
dc Current Limit:
+85 °C
–40 °C
Dynamic Current Limit
(t = < 0.5 µs)
Isolation:
+25 °C
+85 °C
–40 °C
dV/dt Sensitivity†
Test Condition
Measure
Min
Typ
Max
Unit
Vswitch (differential) = –320 V to Gnd
Vswitch (differential) = –60 V to +260 V
Vswitch (differential) = –330 V to Gnd
Vswitch (differential) = –60 V to +270 V
Vswitch (differential) = –310 V to Gnd
Vswitch (differential) = –60 V to +250 V
Iswitch
—
—
1
µA
Iswitch
—
—
1
µA
Iswitch
—
—
1
µA
TLINE = ±10 mA, ±40 mA, TBAT = –2 V
TLINE = ±10 mA, ±40 mA, TBAT = –2 V
TLINE = ±10 mA, ±40 mA, TBAT = –2 V
Per ON-resistance test
condition of SW1, SW2
Iswitch = ILIMIT @ 50 Hz/60 Hz
∆ VON
∆ VON
∆ VON
Magnitude
RON SW1 – RON SW2
VON
—
—
—
—
19.5
—
14.5
0.2
—
28
—
1.0
Ω
Ω
Ω
Ω
—
—
220
V
Vswitch (on) = ±10 V
Vswitch (on) = ±10 V
Break switches in ON state; ringing
access switches off; apply ±1000 V at
10/1000 µs pulse; appropriate secondary protection in place
Iswitch
Iswitch
Iswitch
80
—
—
—
—
2.5
—
250
—
mA
mA
A
Vswitch (both poles) = ±320 V,
Logic inputs = Gnd
Vswitch (both poles) = ±330 V,
Logic inputs = Gnd
Vswitch (both poles) = ±310 V,
Logic inputs = Gnd
—
Iswitch
—
—
1
µA
Iswitch
—
—
1
µA
Iswitch
—
—
1
µA
—
—
200
—
V/µs
* This parameter is not tested in production. Choice of secondary protector should ensure this rating is not exceeded.
† Applied voltage is 100 Vp-p square wave at 100 Hz.
4
Lucent Technologies Inc.
Data Sheet
November 1999
L7582 Tip Ring Access Switch
Electrical Characteristics (continued)
Table 6. Ring Return Switch, 3
Parameter
OFF-state Leakage
Current (SW3):
+25 °C
+85 °C
–40 °C
dc Current Limit
Dynamic Current
Limit (t = < 0.5 µs)
ON-resistance
ON-state Voltage*
Isolation:
+25 °C
+85 °C
–40 °C
Test Condition
Vswitch (differential) = –320 V to Gnd
Vswitch (differential) = –60 V to +260 V
Vswitch (differential) = –330 V to Gnd
Vswitch (differential) = –60 V to +270 V
Vswitch (differential) = –310 V to Gnd
Vswitch (differential) = –60 V to +250 V
Vswitch (on) = ±10 V
Break switches in ON state; ringing access switches
off; apply ±1000 V at 10/1000 µs pulse; appropriate
secondary protection in place
Iswitch (on) = ±0 mA, ±10 mA
Iswitch = ILIMIT @ 50 Hz/60 Hz
dV/dt Sensitivity†
Vswitch (both poles) = ±320 V, Logic inputs = Gnd
Vswitch (both poles) = ±330 V, Logic inputs = Gnd
Vswitch (both poles) = ±310 V, Logic inputs = Gnd
—
Measure Min Typ Max Unit
Iswitch
—
—
1
µA
Iswitch
—
—
1
µA
Iswitch
—
—
1
µA
Iswitch
Iswitch
—
—
200
2.5
—
—
mA
A
∆ VON
VON
—
—
—
—
100
130
Ω
V
Iswitch
Iswitch
Iswitch
—
—
—
—
—
—
—
—
200
1
1
1
—
µA
µA
µA
V/µs
* This parameter is not tested in production. Choice of secondary protector should ensure this rating is not exceeded.
† Applied voltage is 100 Vp-p square wave at 100 Hz.
Table 7. Ringing Access Switch, 4
Parameter
OFF-state Leakage
Current (SW4):
+25 °C
+85 °C
–40 °C
ON Voltage
Ring Generator Current During Ring
Steady-state Current†
Surge Current†
Release Current
ON-resistance
Isolation:
+25 °C
+85 °C
–40 °C
dV/dt Sensitivity‡
Test Condition
Measure
Min
Vswitch (differential) = –255 V to +210 V
Vswitch (differential) = +255 V to –210 V
Vswitch (differential) = –270 V to +210 V
Vswitch (differential) = +270 V to –210 V
Vswitch (differential) = –245 V to +210 V
Vswitch (differential) = +245 V to –210 V
Iswitch (on) = ±1 mA
VCC = 5 V
INACCESS = 0
—
—
—
Iswitch (on) = ±70 mA, ±80 mA
Iswitch
—
—
1
µA
Iswitch
—
—
1
µA
Iswitch
—
—
1
µA
—
IRINGSOURCE
—
—
—
*
3
—
V
mA
—
—
—
∆ Von
—
—
—
—
—
—
500
150
2
—
12
mA
A
µA
Ω
Iswitch
Iswitch
Iswitch
—
—
—
—
—
—
—
—
200
1
1
1
—
µA
µA
µA
V/µs
Vswitch (both poles) = ±320 V, Logic inputs = Gnd
Vswitch (both poles) = ±330 V, Logic inputs = Gnd
Vswitch (both poles) = ±310 V, Logic inputs = Gnd
—
Typ Max Unit
* At the time of publication of this data sheet, the current device design will be a nominal 4 mA. Devices are being redesigned to reduce this
current to less than 2 mA nominally. Consult your Lucent Technologies Microelectronics Group account executive for additional details.
† Choice of secondary protector and series current-limit resistor should ensure these ratings are not exceeded.
‡ Applied voltage is 100 Vp-p square wave at 100 Hz.
Lucent Technologies Inc.
5
Data Sheet
November 1999
L7582 Tip Ring Access Switch
Electrical Characteristics (continued)
Table 8. Loop Access Switches, 5 and 6
Parameter
OFF-state Leakage
Current:
+25 °C
+85 °C
–40 °C
dc Current Limit:
+85 °C
–40 °C
Dynamic Current Limit
(t = <0.5 µs)
ON-resistance:
+25 °C
+85 °C
–40 °C
ON-state Voltage*
Isolation:
+25 °C
+85 °C
–40 °C
dV/dt Sensitivity†
Test Condition
Measure
Min
Typ Max Unit
Vswitch (differential) = –320 V to Gnd
Vswitch (differential) = –60 V to +260 V
Vswitch (differential) = –330 V to Gnd
Vswitch (differential) = –60 V to +270 V
Vswitch (differential) = –310 V to Gnd
Vswitch (differential) = –60 V to +250 V
Iswitch
—
—
1
µA
Iswitch
—
—
1
µA
Iswitch
—
—
1
µA
Vswitch (on) = ±10 V
Vswitch (on) = ±10 V
Break switches in ON state; ringing access
switches off; apply ±1000 V at 10/1000 µs pulse;
appropriate secondary protection in place
Iswitch
Iswitch
Iswitch
80
—
—
—
—
2.5
—
250
—
mA
mA
A
Iswitch (on) = ±10 mA, ±40 mA
Iswitch (on) = ±10 mA, ±40 mA
Iswitch (on) = ±10 mA, ±40 mA
Iswitch = ILIMIT @ 50 Hz/60 Hz
∆ VON
∆ VON
∆ VON
VON
—
—
—
—
45
—
33
—
—
70
—
130
Ω
Ω
Ω
V
Vswitch (both poles) = ±320 V, Logic inputs = Gnd
Vswitch (both poles) = ±330 V, Logic inputs = Gnd
Vswitch (both poles) = ±310 V, Logic inputs = Gnd
—
Iswitch
Iswitch
Iswitch
—
—
—
—
—
—
—
—
200
1
1
1
—
µA
µA
µA
V/µs
* This parameter is not tested in production. Choice of secondary protector should ensure this rating is not exceeded.
† Applied voltage is 100 Vp-p square wave at 100 Hz.
6
Lucent Technologies Inc.
Data Sheet
November 1999
L7582 Tip Ring Access Switch
Electrical Characteristics (continued)
Table 9. Additional Electrical Characteristics
Parameter
Digital Input Characteristics:
Input Low Voltage
Input High Voltage
Input Leakage Current (high)
Input Leakage Current (low)
Power Requirements:
Power Dissipation
VDD Current
VBAT Current
Test Condition
Measure
Min
Typ
—
—
VDD = 5.5 V, VBAT = –75 V,
Vlogicin = 5 V
VDD = 5.5 V, VBAT = –75 V,
Vlogicin = 0 V
—
—
llogicin
—
3.5
—
—
—
—
1.5
—
1
V
V
µA
llogicin
—
—
1
µA
IDD, IBAT
IDD
—
—
3
6
5
10
mW
mW
IDD
IDD
—
—
560 900
0.750 1.9
µA
mA
IBAT
IBAT
—
—
4
4
10
10
µA
µA
—
—
110
10
125
—
150
25
°C
°C
VDD = 5 V, VBAT = –48 V,
idle/talk state or all OFF state,
ringing state or access state
VDD = 5 V,
idle/talk state or all OFF state,
ringing state or access state
VBAT = –48 V,
idle/talk state or all OFF state,
ringing state or access state
Temperature Shutdown Requirements*:
Shutdown Activation Temperature
Shutdown Circuit Hysteresis
—
—
Max Unit
* Temperature shutdown flag (TSD) will be high during normal operation and low during temperature shutdown state.
Zero Cross Current Turn Off
Switching Behavior
The ring access switch (SW4) is designed to turn off on
the next zero current crossing after application of the
appropriate logic input control. This switch requires a
current zero cross to turn off. Switch 4, once on, will
remain in the ON state (regardless of logic input) until a
current zero cross. Therefore, to ensure proper operation of switch 4, this switch should be connected, via
proper impedance, to the ringing generator or some
other ac source. Do not attempt to switch pure dc with
switch 4.
When switching from the power ringing state to the
idle/talk state via simple logic level input control, the
L7582 is able to provide control with respect to the timing when the ringing access contacts are released relative to the state of the line break contacts.
For a detailed explanation of the operation of switch 4,
please refer to the An Introduction to L758X Series of
Line Card Access Switches Application Note.
Lucent Technologies Inc.
Make-before-break operation occurs when the line
break switch contacts are closed (or made) before the
ringing access switch contact is opened (or broken).
Break-before-make operation occurs when the ringing
access contact is opened (broken) before the line
break switch contacts are closed (made).
Using the logic level input pins INring and INaccess,
either make-before-break or break-before-make operation of the L7582 is easily achieved. The logic
sequences for either mode of operation are given in
Table 10 and Table 11. See the Truth Table (Table 13)
for an explanation of the logic states.
7
Data Sheet
November 1999
L7582 Tip Ring Access Switch
Switching Behavior (continued)
The SCR may turn on if:
When using an L7582 in the make-before-break mode,
during the ring-to-idle transition, for a period of up to
one-half the ringing frequency, the ring break switch
and the pnpn-type ring access switch can both be in
the ON state. This is the maximum time after the logic
signal at INRING has transitioned that the ring access
switch is waiting for the next zero current cross, so it
can close. During this interval, current that is limited to
the dc break switch current-limit value will be sourced
from the ring node of the SLIC.
This current is presented to the internal protection circuit.
■
The SCR-type protector is used (A code)
■
By random probability the ring-to-idle transition
occurs during a portion of the ring cycle when the
ringing voltage exceeds the protection circuit SCR
turn-on voltage.
■
Current in excess of the SCR’s turn-on current is also
available.
Once the SCR is triggered on, if the SLIC is capable of
supplying current in excess of the holding current, the
SCR may be latched on by the SLIC.
The probability of this event depends on the characteristics of the given SLIC and of the holding current of the
L7582A device. The SCR hold current distribution is
designed to be safely away from the test limit of
80 mA. The higher the distribution, the lower the probability of the latch.
If this situation is of concern for a given board design,
either use the A series device in the break-before-make
mode (eliminates the original 25 ms current pulse) or
use a B series device (eliminates the SCR).
Table 10. Make-Before-Break Operation
ACCESS INPUT TSD
8
0V
0V
5V
0V
0V
0V
State
Timing
Float Power Ringing
—
Float Make-before- SW4 waiting for next zero
break
current crossing to turn off
maximum time—one-half of
ringing. In this transition
state, current that is limited
to the dc break switch current-limit value will be
sourced from the ring node
of the SLIC.
Float
Idle/Talk
Zero cross current has
occurred.
Break
Switches
1&2
Ring
Return
Switch
3
Line
Ring
Access Access
Switch Switches
5&6
4
Open
Closed
Closed
Open
Closed
Closed
Open
Open
Closed
Open
Open
Open
Lucent Technologies Inc.
Data Sheet
November 1999
L7582 Tip Ring Access Switch
Switching Behavior (continued)
Table 11. Break-Before-Make Operation
ACCESS INPUT
0V
5V
5V
5V
5V
5V
0V
0V
TSD
State
Timing
Float
Power
—
Ringing
Float All Off Hold this state for ≤25 ms.
SW4 waiting for zero current to turn off.
Float All Off Zero current has occurred
and SW4 has opened.
Float Idle/Talk Release break switches.
Break
Switches
1&2
Ring
Return
Switch 3
Ring
Access
Switch 4
Line Access
Switches
5&6
Open
Closed
Closed
Open
Open
Open
Closed
Open
Open
Open
Open
Open
Closed
Open
Open
Open
Notes:
Break-before-make operation can also be achieved using TSD as an input. In lines two and three of Table 11, instead of using the logic input pins
to force the all OFF state, force TSD to ground. This will override the logic inputs and also force the all OFF state. Hold this state for 25 ms. During this 25 ms all OFF state, toggle the inputs from 10 (ringing state) to 00 (idle/talk state). After 25 ms, release TSD to return switch control to
the input pins which will set the idle talk state.
When using the L7582 in this mode, forcing TSD to ground will override the INPUT pins and force an all OFF state. Setting TSD to 5 V will allow
switch control via the logic INPUT pins. However, setting TSD to 5 V will also disable the thermal shutdown mechanism. This is not recommended. Therefore, to allow switch control via the logic INPUT pins, allow TSD to float.
Thus, when using TSD as an input, the two recommended states are 0 (overrides logic input pins and forces all OFF state) and float (allows
switch control via logic input pins and thermal shutdown mechanism is active). This may require use of an open collector buffer.
Also note that TSD operation in L7582 is different than TSD operation of the L7581, where application of 5 V does not disable the thermal shutdown mechanism.
Power Supplies
Both the 5 V and battery supply are brought onto the
L7582. The L7582 requires only the 5 V supply for
switch operation; that is, state control is powered exclusively off of the 5 V supply. Because of this, the L7582
offers extremely low power dissipation, both in the idle
and active states.
The battery voltage is not used for switch state control.
The battery is used as a reference voltage by the
integrated secondary protection circuit. When the voltage at TBAT or RBAT drops 2 V to 4 V below the battery,
the integrated SCR will trigger, thus preventing
fault-induced overvoltage situations at the TBAT/RBAT
nodes.
Loss of Battery Voltage
The L7582 is designed such that the device will enter
the all OFF state if the battery rises above –10 V and
will remain off until the battery drops below –15 V.
Monitoring the battery for the automatic shutdown feature will draw a small current from the battery, typically
4 µA. This will add slightly to the overall power dissipation of the device.
Impulse Noise
Using the L7582 will minimize and possibly eliminate
the contribution to the overall system impulse noise
that is associated with ringing access switches.
Because of this characteristic of the L7582, it may not
be necessary to incorporate a zero cross switching
scheme. This ultimately depends upon the characteristics of the individual system and is best evaluated at
the board level.
As an additional protection feature, the L7582 monitors
the battery voltage. Upon loss of battery voltage, the
L7582 will automatically enter an all OFF state and
remain in that state until the battery voltage is restored.
Lucent Technologies Inc.
9
L7582 Tip Ring Access Switch
Protection
Integrated SLIC Protection
Diode Bridge/SCR
In the L7582Axx version, protection to the SLIC device
or other subsequent circuitry is provided by a combination of current-limited break switches, a diode bridge/
SCR clamping circuit, and a thermal shutdown mechanism. In the L7582Bxx version, protection to the SLIC
device or other subsequent circuitry is provided by a
combination of current-limited break switches, a diode
bridge, and a thermal shutdown mechanism.
In both versions, during a positive lightning event, fault
current is directed to ground via steering diodes in the
diode bridge. Voltage is clamped to a diode drop above
ground. In the A version, negative lightning causes the
SCR to conduct when the voltage goes 2 V to 4 V more
negative than the battery. Fault currents are then
directed to ground via the SCR and steering diodes in
the diode bridge.
Note that for the SCR to foldback or crowbar, the ON
voltage (see Table 11) of the SCR must be less negative than the battery reference voltage. If the battery
voltage is less negative than the SCR ON voltage, the
SCR will conduct fault currents to ground; however, it
will not crowbar.
In the B version, negative lightning is directed to battery
via steering diodes in the diode bridge.
For power cross and power induction faults, in both versions, the positive cycle of the fault is clamped a diode
drop above ground and fault currents are steered to
ground. In the A version, the negative cycle will cause
the SCR to trigger when the voltage exceeds the battery reference voltage by 2 V to 4 V. When the SCR
triggers, fault current is steered to ground. In the B version, the negative cycle of the power cross is steered to
battery.
Current Limiting
During a lightning event, the current that is passed
through the break switches and presented to the integrated protection circuit and subsequent circuitry is limited by the dynamic current-limit response of the break
switches (assuming idle/talk state). When the voltage
seen at the TLINE/RLINE nodes is properly clamped by
an external secondary protector, upon application of a
1000 V 10 x 1000 pulse (LSSGR lightning), the current
seen at the TBAT/RBAT nodes will typically be a pulse of
magnitude 2.5 A and duration less than 0.5 µs.
10
Data Sheet
November 1999
During a power cross event, the current that is passed
through the break switches and presented to the integrated protection circuit and subsequent circuitry is limited by the dc current-limit response of the break
switches (assuming idle/talk state). The dc current limit
is specified over temperature between 100 mA and
250 mA.
Note that the current-limit circuitry has a negative temperature coefficient. Thus, if the device is subjected to
an extended power cross, the value of current seen at
TBAT/RBAT will decrease as the device heats due to the
fault current. If sufficient heating occurs, the temperature shutdown mechanism will activate and the device
will enter an all off mode.
Temperature Shutdown Mechanism
When the device temperature reaches a minimum of
110 °C, the thermal shutdown mechanism will activate
and force the device into an all OFF state, regardless of
the logic input pins. Pin TSD, when used as an output,
will read 0 V when the device is in the thermal shutdown mode and +VDD during normal operation.
During a lightning event, due to the relatively short
duration, the thermal shutdown will not typically activate.
During an extended power cross, the device temperature will rise and cause the device to enter the thermal
shutdown mode. This forces an all off mode, and the
current seen at TBAT/RBAT drops to zero. Once in the
thermal shutdown mode, the device will cool and exit
the thermal shutdown mode, thus reentering the state it
was in prior to thermal shutdown. Current, limited to the
dc current-limit value, will again begin to flow and
device heating will begin again. This cycle of entering
and exiting thermal shutdown will last as long as the
power-cross fault is present.
If the magnitude of power is great enough, the external
secondary protector could trigger, thereby shunting all
current to ground.
In the L7582, the thermal shutdown mechanism can be
disabled by forcing the TSD pin to +VDD. This functionality differs from the L7581, whose thermal shutdown
mechanism cannot be disabled.
Lucent Technologies Inc.
Data Sheet
November 1999
Protection (continued)
Integrated SLIC Protection (continued)
External Secondary Protector
With the above integrated protection features, only one
overvoltage secondary protection device on the loop
side of the L7582 is required. The purpose of this
device is to limit fault voltages seen by the L7582 so as
not to exceed the breakdown voltage or input-output
isolation rating of the device. To minimize stress on the
L7582, use of a foldback- or crowbar-type device is recommended. A detailed explanation and design equations on the choice of the external secondary
protection device are given in the An Introduction to
L758X Series of Line Card Access Switches Application Note. Basic design equations governing the choice
of external secondary protector are given below:
■
■
■
L7582 Tip Ring Access Switch
where:
VBATmax—Maximum magnitude of battery voltage.
Vbreakovermax—Maximum magnitude breakover voltage of external secondary protector.
Vbreakovermin—Minimum magnitude breakover voltage
of external secondary protector.
Vbreakdownmin(break)—Minimum magnitude breakdown
voltage of L7582 break switch.
Vbreakdownmin(ring)—Minimum magnitude breakdown
voltage of L7582 ring access switch.
Vringingpeakmax—Maximum magnitude peak voltage of
ringing signal.
Series current-limiting fused resistors or PTCs should
be chosen so as not to exceed the current rating of the
external secondary protector. Refer to the manufacturer’s data sheet for requirements.
|VBATmax| + |Vbreakovermax| < |Vbreakdownmin(break)|
|Vringingpeakmax| + |VBATmax| + |Vbreakovermax| <
|Vbreakdownmin(ring)|
|Vringingpeakmax| + |VBATmax| < |Vbreakovermin|
Table 12. Electrical Specifications, Protection Circuitry
Parameters Related to Diodes (in Diode Bridge)
Parameter
Test Condition
Measure
Min
Voltage Drop @ Continuous CurApply ±dc current limit
Forward
—
rent (50 Hz/60 Hz)
of break switches
Voltage
Voltage Drop @ Surge
Apply ±dynamic curForward
—
Current
rent limit of break
Voltage
switches
Parameters Related to Protection SCR
Surge Current
—
—
—
—
—
—
Gate Trigger Current*†
†
Gate Trigger Current Temperature
—
—
—
Coefficient
Hold Current
—
—
70
Gate Trigger Voltage
Trigger current
—
VBAT – 4
Reverse Leakage Current
VBAT
—
—
§
ON-State Voltage
0.5 A, t = 0.5 µs
VON
—
2.0 A, t = 0.5 µs
—
—
Typ
—
Max
3
Unit
V
5
—
V
—
25
–0.5
‡
A
mA
%/°C
—
—
—
–3
–5
50
—
—
VBAT – 2
1.0
—
—
mA
V
µA
V
V
* Previous versions of this data sheet specified a Trigger Current of 50 mA minimum. Trigger Current is defined as the minimum current drawn
from tip and ring to turn on the SCR. The specification in this data sheet is Gate Trigger Current, which is defined as the maximum current
that can flow into the battery before the SCR turns on.
† Typical at 25 °C.
‡ Twice ± dynamic current limit of break switches.
§ In some instances, the typical ON-state voltage can range as low as –25 V.
Lucent Technologies Inc.
11
Data Sheet
November 1999
L7582 Tip Ring Access Switch
Typical Performance Characteristics
CURRENT
LIMITING
+I
ILIMIT
2/3 RON
dc CURRENT-LIMIT
BREAK SWITCHES
VBAT – 2
VBAT – 4
RON
–1.5 V
VBAT
–V
VON
<1 µA
3V
1.5 V
RON
+V
2/3 RON
ILIMIT
CURRENT
LIMITING
50 mA
–I
12-2311 (F)
dc CURRENT LIMIT
(OF BREAK SWITCHES)
Figure 5. Switches 1—3
IH
12-2309.f (F)
Figure 3. Protection Circuit A Version
+I
RON
dc CURRENT-LIMIT
BREAK SWITCHES
–VOS
–V
VBAT – 3
+VOS
+V
VBAT
<1 µA
3V
–I
12-2312 (F)
dc CURRENT LIMIT
(OF BREAK SWITCHES)
Figure 6. Switch 4
12-2309.b (F)
Figure 4. Protection Circuit B Version
12
Lucent Technologies Inc.
Data Sheet
November 1999
L7582 Tip Ring Access Switch
Application
VBAT
REFERENCE
TIP
SW5
LINE
TEST
ACCESS
R1
SW3
RINGING
RETURN
TIP
SW1 BREAK
SCR
AND
TRIP
CKT
CROWBAR
PROTECTION
R2
BATTERY
FEED
SW2 BREAK
SW6
LINE
TEST
ACCESS
RING
RING
SW4
RINGING
ACCESS
RING
GENERATOR
BATTERY
12-2366.c (F)
Figure 7. Typical TRAS Application, Idle, or Talk State Shown
Table 13. Truth Table
Input
Access
0V
0V
5V
0V
0V
5V
5V
5V
Don’t Care Don’t Care
1.
2.
3.
4.
5.
6.
TSD
5 V/Float1
5 V/Float1
5 V/Float1
5 V/Float1
0 V2
Tip
Break
Switch
On
Off
Off
Off
Off
Ring
Break
Switch
On
Off
Off
Off
Off
Ringing
Return
Switch
Off
On
Off
Off
Off
Ring
Switch
Off
On
Off
Off
Off
Tip
Access
Switch
Off
Off
On
Off
Off
Ring
Access
Switch
Off3
Off4
On5
Off6
Off6
If TSD = 5 V, the thermal shutdown mechanism is disabled. If TSD is floating, the thermal shutdown mechanism is active.
Forcing TSD to ground overrides the logic input pins and forces an all OFF state.
Idle/Talk state.
Power ringing state.
Test out or message waiting state.
All OFF state.
A parallel in/parallel out data latch is integrated into the
L7582. Operation of the data latch is controlled by the
logic level input pin LATCH. The data input to the latch
is the INRING and INACCESS pins of the L7582, and the
output of the data latch is an internal node used for
state control.
When the LATCH control pin is at logic 0, the data latch
is transparent and data control signals flow directly
from INRING and INACCESS, through the data latch to
state control. Any changes in INRING and INACCESS will
be reflected in the state of the switches.
Lucent Technologies Inc.
When the LATCH control pin is at logic 1, the data latch
is active—the L7582 will no longer react to changes at
the INRING and INACCESS control pins. The state of the
switches is now latched; that is, the state of the
switches will remain as they were when the LATCH
input transitioned from logic 0 to logic 1. The switches
will not respond to changes in INRING and INACCESS as
long as LATCH is held high.
Note that the TSD input is not tied to the data latch. TSD
is not affected by the LATCH input. TSD input will override state control via INRING, INACCESS, and LATCH.
13
Data Sheet
November 1999
L7582 Tip Ring Access Switch
Outline Diagrams
16-Pin, Plastic SOG (L7582AAE/BAE)
Note: The dimensions in this outline diagram are intended for informational purposes only. For detailed schematics
to assist your design efforts, please contact your Lucent Technologies Sales Representative.
L
N
B
1
PIN #1 IDENTIFIER ZONE
W
H
SEATING PLANE
0.10
1.27 TYP
0.51 MAX
0.61
0.28 MAX
Number
of Pins
(N)
Maximum
Length
(L)
Maximum Width
Without Leads
(B)
Maximum Width
Including Leads
(W)
Maximum Height
Above Board
(H)
16
10.49
7.62
10.64
2.67
5-4414 (F)
14
Lucent Technologies Inc.
Data Sheet
November 1999
L7582 Tip Ring Access Switch
Outline Diagrams (continued)
16-Pin, Plastic DIP (L7582AC/BC)
Note: The dimensions in this outline diagram are intended for informational purposes only. For detailed schematics
to assist your design efforts, please contact your Lucent Technologies Sales Representative.
L
N
B
1
W
PIN #1 IDENTIFIER ZONE
H
SEATING PLANE
0.38 MIN
2.54 TYP
0.58 MAX
Number
of Pins
(N)
Maximum
Length
(L)
Maximum Width
Without Leads
(B)
Maximum Width
Including Leads
(W)
Maximum Height
Above Board
(H)
16
20.57
6.48
7.87
5.08
5-4410 (F)
Lucent Technologies Inc.
15
Data Sheet
November 1999
L7582 Tip Ring Access Switch
Ordering Information
Device Part No.
ATTL7582AAE
ATTL7582AAE-TR*
ATTL7582AC
ATTL7582BAE
ATTL7582BAE-TR*
ATTL7582BC
Description
Tip Ri ng Access Switch
Tip Ri ng Access Switch
Tip Ri ng Access Switch
Tip Ri ng Access Switch
Tip Ri ng Access Switch
Tip Ri ng Access Switch
Package
16-pin SOG
16-pin SO G (Tape & Reel)
16-pin DIP
16-pin SOG
16-pin SO G (Tape & Reel)
16-pin DIP
Comcode
107338543
107338576
107394181
107394231
107394256
107394207
*Devices o n tape an d reel must be ordered i n 1000-piece inc rement s.
For additi onal
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Lucent Techn ologies I nc. re ser ves t he right t o make chan ges to the p roduct (s) or in formation c ontain ed he rein with outono
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tice. Ni s assum ed as a res ult of t heir us e or applicatio n. No
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Copyright © 1999 Luce nt Technologie s Inc.
All Rights Res er ved
November 1999
DS00-051ALC (Replaces DS99-015ALC)
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