
Lucent Technologies Inc.
9
Data Sheet
October 1998
Relay, and Protector (SRP) for Long Loop and TR-57 Applications
L8574D Resistive Subscriber Line Interface Circuit (SLIC), Ring
Electrical Characteristics
(continued)
Fault Protection
Pins PT, PR, and V
BF
Pins PT, PR, and V
BF
are protected by SCRs which clamp surge currents (both positive and negative) to FGND. If
the SCR on PR or V
BF
triggers due to a negative surge, the L8574 automatically switches to the disconnect state
while the SCR is conducting current above its hold current. After the SCR releases, the L8574 automatically
switches back to the operating state prior to the SCR trigger.
Table 5. Electrical Characteristics of Pins PT, PR, and V
BF
1.This parameter is not tested in production. It is guaranteed by design and device characterization.
2.Applied voltage is 50 Vpp square wave at 100 Hz to measure dV/dt sensitivity.
Parameter
Min
Typ
Max
Unit
PT and PR:
Surge Current
1
:
Lightning—10
μ
s x 1000
μ
s
Lightning—2
μ
s x 10
μ
s
Power Cross—60 Hz, 50 ms
Power Cross—60 Hz, 1 s
Power Cross—60 Hz, 15 min.
SCR Trigger Voltage Pin PT:
Positive
Negative
dc Transient Response
SCR Trigger Voltage Pin PR:
Positive
Negative
SCR Hold Current (positive and negative)
V
BF
:
Surge Current
1
:
Lightning—10
μ
s x 1000
μ
s
Lightning—2
μ
s x 10
μ
s
Power Cross—60 Hz, 50 ms
Power Cross—60 Hz, 1 s
Power Cross—60 Hz, 15 min.
SCR Trigger Voltage:
Positive
Negative
SCR Hold Current (positive and negative)
Trigger Current (if from a power supply—PT, PR, and V
BF
)
dV/dt Sensitivity
1, 2
(PT, PR, and V
BF
)
—
—
—
—
—
—
—
—
—
—
±
1
±
2.5
600
200
50
A
A
mArms
mArms
mArms
V
CCA
– 2
–25
–25
—
—
—
V
CCA
+ 4
–35
–55
V
V
V
150
–220
10
—
—
—
280
320
—
V
V
mA
—
—
—
—
—
—
—
—
—
—
±
5.5
±
13
3
800
150
A
A
Arms
mArms
mArms
150
–220
10
—
—
—
—
—
—
500
280
–320
—
±
250
—
V
V
mA
μ
A
V/
μ
s