Data Sheet
May 2001
L8576B Dual Ringing SLIC
Electrical Characteristics (continued)
Pretrip will not occur for the circuits shown below, per GR-909, 4.5.9.
200 Ω
TIP
RING
SWITCH CLOSES FOR LESS THAN 12 ms
6 µF
TIP
RING
10 kΩ
12-2572(F).d
Figure 4. Pretrip Circuit
Table 5. Battery Feed
Parameter
Min
Typ
Max
Unit
Loop Resistance Range1
(3.17 dBm overload into 600 Ω):
ILOOP = 20 mA at VBAT = –65 V
Longitudinal Current Capability per Wire2
1000
8.5
—
—
—
Ω
15
mArms
Current Limit3 RLOOP = 100 Ω:
dc Loop
20
50
24
60
28
70
mA
mA
Instantaneous4
Tip or Ring Drive Current = dc + Longitudinal + Signal Currents
Signal Current
65
5
—
—
—
—
—
—
mA
mArms
V
Powerup Open Loop Voltage Level
Differential Voltage (RNGNG = 0, NDISC = 1, B2 = 1,
VBAT = –65 V)
|VBAT + 10|
Disconnect State:
PT or PR Current (VBAT < VPT < 0 V)
PT or PR Resistance (VBAT < VPT < 0 V)
–1
100
—
—
1
—
mA
kΩ
dc Feed Resistance
—
60
70
Ω
Longitudinal to Metallic Balance—IEEE5 Standard 4556:
200 Hz to 1 kHz
1 kHz to 3 kHz
54
48
67
62
—
—
dB
dB
Metallic to Longitudinal (Harm) Balance7:
200 Hz to 4 kHz
35
—
—
dB
1. Assumes 2 x 30 Ω external protection resistors. Note the useful range of the device may be determined by the ringing or supervision range
rather than the ac characteristics.
2. The longitudinal current is independent of dc loop current.
3. Current limit ILIM is programmed by a resistor, RPROG, from pin IPROG to pin DCOUT RPROG (kΩ) = 3.5 x (ILIM – 9.2) mA. The current limit has a
slope vs. loop voltage of 6 kΩ. To control power dissipation, it is recommended that the default current limits be utilized, i.e., RPROG = 51.1 kΩ
for 24 mA nominal loop current limit.
4. Instantaneous current limit minimizes inrush current at the onset of an off-hook condition. Inrush current is only limited when in the forward
battery state. The device will settle into a dc loop current-limit value within 400 ms after off-hook.
5. IEEE is a registered trademark of The Institute of Electrical and Electronics Engineers, Inc.
6. Assumes the external protection resistors are matched to 1%.
7. This parameter is not tested during production. It is guaranteed by design and device characterization.
Agere Systems Inc.
11
AGERE [ AGERE SYSTEMS ]
