LUCL8567AAU-D AGERE [Agere Systems], LUCL8567AAU-D Datasheet - Page 34

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

L8567 SLIC for
People’s Republic of China Applications
dc Characteristics
Loop Range
The following equation is used to determine the dc loop
range.
Where:
R
|V
V
I
R
R
Example 1, Standard Loop:
Calculate loop range with battery voltage of 48 V, SLIC
maximum overhead of 7.8 V, SLIC dc feed resistance of
65 , 18 mA loop current requirement, worst-case
resistance of L758X switch of 28 , and 50
tion resistor with worst-case 10% tolerance of 55 .
Example 2, Extended Loop:
With a –65 V battery voltage, assuming a SLIC nominal
overhead of 7.1 V, SLIC dc feed resistance of 110 ,
18 mA loop current requirement, worst-case resistance
of L758X switch of 28 , and 50
with worst-case 10% tolerance of 55
maximum loop length?
34
34
L
2941
OH
L
P
dc
BAT
= dc loop current.
= dc loop range.
R
= series protection resistor and resistance of L758X
= SLIC dc feed resistance.
= SLIC overhead voltage.
R
L
| = magnitude of battery voltage.
solid-state switch (if used).
L
=
= 1937
48 V 7.8 V
------------------------------------
=
0.018 A
65 V 7.1 V
------------------------------------
R
L
0.018 A
–
=
–
> 1800
-------------------------------- 2R
V
BAT
–
I
L
–
–
2
(continued)
V
2
OH
55
–
55
+
28
+
protection resistor
P
28
–
, what is the
–
R
130
dc
–
110
protec-
dc Applications
On-Hook Transmission
In order to drive an on-hook ac signal, the SLIC must
set up the tip and ring voltage to a value less than the
battery voltage. The amount that the open loop voltage
is decreased relative to the battery is referred to as the
overhead voltage. Expressed as an equation,
Without this buffer voltage, amplifier saturation will
occur and the signal will be clipped. The L8567 is auto-
matically set at the factory to allow undistorted on-hook
transmission of a 3.17 dBm signal into a 900
impedance.
The drive amplifiers are capable of 4 Vrms minimum
(V
tee is:
The peak voltage at output of tip and ring amplifiers is
related to the peak signal voltage by:
AMP
V
T/R
+
–
). So, the maximum signal the device can guaran-
Figure 27. SLIC 2-Wire Output Stage
[Z
T/R
]
Vamp =
V
V
T/R
OH
R
R
= |V
P
=
P
v
4 V
BAT
T/R
| – (V
------------------------- -
1
Z
T/R
+
Lucent Technologies Inc.
Z
PT
-----------
2R
Z
T/R
+
V
T/R
– V
AMP
+
–
2R
P
PR
P
August 1999
)
Data Sheet
ac loop
12-2563 (F)