LUCL8567AAU-D AGERE [Agere Systems], LUCL8567AAU-D Datasheet - Page 35

• Manufacturer Part Number: LUCL8567AAU-D
• Description: SLIC for Peoples Republic of China Applications
• Manufacturer: AGERE [Agere Systems]

Data Sheet
August 1999
dc Applications
On-Hook Transmission
In addition to the required peak signal level, the SLIC
needs about 2 V from each power supply to bias the
amplifier circuitry. It can be thought of as an internal
saturation voltage. Combining the saturation voltage
and the peak signal level, the required overhead can be
expressed as:
where V
between the tip/ring amplifiers and V
R
loop impedance.
Example:
Determine the required overhead to transmit on-hook
(I
Assume use of 50
tolerance or 55
worst-case resistance of the switch is 28 . Note the
minimum overhead voltage of the L8567 is 6.4 V.
V
3.17 dBm = 20log
Vrms = 1.296 V
V
Vrms = 1.296 V
V
V
Thus, an overhead of 6.17 V is needed for on-hook
transmission of a 3.17 dBm signal into a 900
The L8567 has a minimum overhead of 6.4 V.
Lucent Technologies Inc.
LOOP
ON
ON
ON
OH
P
( ) is the protection resistor value. Z
= 4.0 +
= 4.0 +
= 4.0 +
= 6.17 V < 6.4 V
= 0) a 3.17 dBm ac signal into a 900
V
SAT
O H
is the combined internal saturation voltage
=
1
1
1
+
+
+
V
2
--------------------------------- -
2
--------------------------------- -
2 55
--------------------------- -
SA T
and an L7583 solid-state switch. The
---------------------------- -
----------------------- -
900
V
protection resistors with a 10%
55
900
55
900
+
10
900
rms
+
(continued)
–
28
+
+
1
3
28
28
2
+
-----------
2R
Z
(continued)
2 1.296
T/R
2 V
2 V
P
v
rms
rms
BAT
T/R
T/R
(4.0 V typical).
( ) is the ac
ac lead.
ac load.
Supervision
Both the loop closure and ring trip supervision func-
tions are included on the L8567 SLIC. The outputs of
these two supervision functions are internally wired-
ORed together to form a single output NSTAT. The
wired-OR connection of the loop supervision and ring
trip detector is also available on pin NLED. This pin has
sufficient drive capability to drive an LED. This pin is an
open-collector output, so multiple pins can be used to
drive a common LED. Also included is a SLIC thermal
shutdown indicator, NTSD.
Note that the ring trip detector is not active in the low-
power scan state. The ring trip detector must be active
prior to applying power ringing to the subscriber loop.
Activate the ring trip detector by putting the L8567 SLIC
into the powerup mode before applying power ringing
to the subscriber loop.
Loop Closure
The on-hook to off-hook loop closure threshold is inter-
nally set to a nominal 11 mA at V
nominal 2 mA hysteresis. This means that the off-hook
to on-hook threshold will be a nominal 2 mA less than
the on-hook to off-hook threshold. The loop closure
threshold will track with battery voltage, increasing as
the battery gets more negative. The loop closure com-
parator has built-in longitudinal rejection, eliminating
the need for an external 50 Hz/60 Hz filter. The loop
closure detector is valid during scan, forward, and
reverse active states.
People’s Republic of China Applications
BAT
= –48 V. There is a
L8567 SLIC for
35