LUCL9310AP-D AGERE [Agere Systems], LUCL9310AP-D Datasheet - Page 41

• Manufacturer Part Number: LUCL9310AP-D
• Description: Line Interface and Line Access Circuit Full-Feature SLIC,Ringing Relay,and Test Access Device
• Manufacturer: AGERE [Agere Systems]

July 2001
Protection
Ring Mode Response at PT/PR
In this mode, the line break switches are off and the
ring access and ring return switch is on. The secondary
protectors must ensure that the minimum off-state volt-
age rating of the line break switches is not exceeded.
Note that the maximum differential voltage is the posi-
tive zener rating of the protection device less the bat-
tery voltage which will appear on the line feed side of
the switch.
The ring access switch is a pnpn type switch. This
switch has no internal current limiting. Thus, through
external current limit, the user must ensure that the
surge ratings (both dynamic and dc for lightning and
power cross faults) are not exceeded. A minimum
400
also will set the ring trip threshold. See the Ring Trip
section within the Supervision section of this data sheet.
During a lightning fault (typical 1000 V 10 x 700 s
applied surge), the current-limited tip return switch will
pass, typically 2.5 A for 0.5 s before forcing the switch
off. Once in the off state, the external protection device
must ensure that the off-state voltage rating of 320 V is
not exceeded.
For power cross for lower-voltage faults, the tip side
power ringing return switch will behave like the line
break switches. However, this switch does not have the
foldback clamping feature that is included in the line
break switches; thus, in the on state, the voltage seen
by the tip side power ringing return switch before dam-
age is less than the line break switches. The on-state
voltage of the line break switches can go up to the off-
state voltage rating. The tip side power ringing return
voltage should see less than 130 V in the on state.
Thus, the secondary protector on the tip side should
have a maximum crowbar voltage of 130 V. With typical
protection device tolerance, this implies a minimum
clamping voltage of 100 V. The users should ensure,
based on minimum loop length, ringing load, and peak
ring signal voltage, that the ring signal is not distorted
by the (lower) voltage rating of the tip-side protector.
Internal Tertiary Protection
The external secondary protector and switch current
limit protect the 320 V high-voltage switches from light-
ning and power cross conditions. Integrated into the
LILAC IC is an internal tertiary protection scheme that
is meant to protect the 90 V SLIC portion of the device
from residue fault current and voltages that may be
Agere Systems Inc.
ring feed resistor is recommended. This resistor
(continued)
Full-Feature SLIC, Ringing Relay, and Test Access Device
passed through the switches to the actual SLIC inputs.
This scheme includes an internal diode bridge voltage
clamp and a battery out of range detector that forces
an all-off condition if the battery voltage falls high or low
out of the specified operating range.
Diode Bridge
The internal inputs of the actual SLIC chip are clamped
to ground and to V
Residual positive fault currents are clamped to ground
and residual negative fault currents are clamped to bat-
tery. This implies that the battery have some current-
sinking capability.
High common-mode currents, as may be seen under a
fault condition, will be sensed and reduced to zero by
the battery monitor circuit (see Battery Out of Range
Detector: High [Magnitude] section). However, this
detector will not prevent longitudinal current from flow-
ing into battery. The battery supply must have the abil-
ity to sink longitudinal currents as specified in the
longitudinal current capability requirement in Table 10.
Battery Out of Range Detector: High (Magnitude)
This feature is useful in remote power applications
where a dc-dc converter with limited ability to sink cur-
rent is used as the primary battery supply. Under a fault
condition, the diode bridge will want to sink current into
the battery. As a function of the dc-dc converter input
capacitance and design, this current may cause the
magnitude of supply voltage to rise and ultimately
cause damage to the supply. To prevent damage to the
supply, the LILAC device will monitor the battery supply
voltage. If the magnitude of the battery rises above the
maximum specified operating battery, the battery out of
range detector will force the line break switches and
ring access switches into an all-off state, and will also
force the SLIC into the disconnect state. This will stop
the current flow into the battery, preventing damage to
the battery fault conditions. NSTAT is forced low during
this mode of operation.
Battery Out of Range Detector: Low (Magnitude)
The LILAC device will monitor the battery supply volt-
age. If the magnitude of the battery drops below the
minimum specified operating battery, the battery out of
range detector will force the line break switches and
ring access switches into an all-off state, and will also
force the SLIC into the disconnect state. NSTAT is
forced low during this mode of operation.
BAT1
by an integrated diode bridge.
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