LUCL9500 AGERE [Agere Systems], LUCL9500 Datasheet - Page 24

• Manufacturer Part Number: LUCL9500
• Description: High-Voltage Ringing SLIC for VolP Applications
• Manufacturer: AGERE [Agere Systems]

High-Voltage Ringing SLIC for VoIP Applications
Applications
Power Ring
The device offers a ring mode, in which a balanced
power ring signal is provided to the tip/ring pair. During
the ring mode, a user-supplied low-voltage ring signal
is input to the device’s RING
amplified to produce the balanced power ring signal.
The user may supply a sine wave input, PWM input, or
a square wave to produce sinusoidal or trapezoidal
ringing at tip and ring.
Various crest factors are shown below for illustrative
purposes.
Note: Slew rate = 5.65 V/ms; trise = tfall = 23 ms; pwidth = 2 ms;
Note: Slew rate = 10.83 V/ms; trise = tfall = 12 ms; pwidth = 13 ms;
24
Figure 10. Ringing Waveform Crest Factor = 1.2
Figure 9. Ringing Waveform Crest Factor = 1.6
period = 50 ms.
period = 50 ms.
–20
–40
–60
–80
–20
–40
–60
–80
80
60
40
20
80
60
40
20
0.00
0.00
0
0
0.02 0.06
0.02 0.06
(continued)
0.04 0.08
0.04 0.08
TIME (s)
TIME (s)
0.10
0.10
IN
0.12
0.12
input. This signal is
0.14
0.14
0.16
0.16
0.18
0.18
0.20
0.20
12-3346a (F)
12-3347a (F)
Sine Wave Input Signal and Sine Wave Power Ring
Signal Output
The low-voltage sine wave input is applied differentially
or single ended to the L9500 at pins RING
RING
RING
the subscriber loop. The differential gain from RING
to tip and ring is a nominal 70.
When the device enters the ring mode, the tip/ring
overhead set at OVH and the scan clamp circuit are
disabled, allowing the voltage magnitude of the power
ring signal to be maximized. Additionally, in the ring
mode, the loop current limit is increased 2.5X the value
set by the V
The magnitude of the power ring voltage will be a func-
tion of the gain of the ring amplifier, the high-voltage
battery, and the input signal at RING
of the signal at RING
age at RING
ring voltage at tip and ring will increase linearly, per the
gain of 70, until the tip and ring drive amplifiers begin to
saturate. Once the tip and ring amplifiers reach satura-
tion, further increases of the input signal will cause clip-
ping distortion of the power ring signal at tip and ring.
The ring signal will appear balanced on tip and ring.
That is, the power ring signal is applied to both tip and
ring, with the signal on tip 180 out of phase from the
signal on ring.
It is recommended that the input level at RING
adjusted so that the power ring signal at tip and ring is
just at the edge or slightly clipping. This gives maxi-
mum power transfer with minimal distortion of the sine
wave. The tip side will saturate at a nominal 1 V above
ground. The ring side will saturate at a nominal 3 V
above battery. The input circuit for a sine wave along
with waveforms to illustrate the tip and ring saturation
is shown in Figure 9.
The point at which clipping of the power ring signal
begins at tip and ring is a function of the battery volt-
age, the input capacitor at RING
at RING
dal ringing waveform may be left on at RING
state table, the ring signal will be removed from tip and
ring even if the low-voltage input is still present at
RING
INN
INP
IN
.
IN
. During the ring mode, the signals at pins
and RING
and Vcc. During nonring modes, the sinusoi-
PROG
IN
is increased, the magnitude of the power
voltage.
INN
IN
are amplified and presented to
is 0 V to Vcc. As the input volt-
IN
, and the input signal
September 2001
Agere Systems Inc.
IN
. The input range
INP
IN
and
. Via the
IN
be
IN