
Data Sheet
July 2001
Forward Battery SLIC and Ringing Relay for TR-57 Applications
L9312 Line Interface and Line Access Circuit
8
Agere Systems Inc.
Pin Information
12-3522f (F)
Figure 2. 44-Pin PLCC
Table 1. Pin Descriptions
Pin
1
Symbol
LCTH
Type
I
Name/Function
Loop Closure Program Input.
Connect a voltage source to this point to program the
loop closure threshold. Voltage source may be external and must be connected
through a resistor, or derived via a resistor divider from V
REF
. A programmable exter-
nal voltage source may be used to provide software control of the loop closure
threshold.
SLIC Internal Reference Voltage.
Output of internal 2.35 V SLIC reference voltage.
Overhead Voltage Program Input.
Connect a voltage source to this point to pro-
gram the overhead voltage. Voltage source may be external or derived via a resistor
divider from V
REF
. A programmable external voltage source may be used to provide
software control of the overhead voltage. If a resistor or voltage source is not con-
nected, the overhead voltage will default to approximately 5.5 V (sufficient to pass
3.14 dBm in to 900
). If the default overhead is desired, connect this pin to ground.
Current-Limit Program Input.
Connect a voltage source to this point to program the
dc current limit. Voltage source may be external or derived via a resistor divider from
V
REF
. A programmable external voltage source may be used to provide software con-
trol of the loop closure threshold.
Filter Capacitor.
Connect a capacitor from this node for filtering.
Filter Capacitor.
Connect a capacitor from this node to OVH to control the rate of
change of the overhead voltage. If controlled overhead is not desired, leave this node
open.
No Connect.
May not be used as a tie point.
2
3
V
REF
OVH
O
I
4
V
PROG
I
5
6
CF2
CF1
—
—
7,
8,
17,
18,
34
NC
—
7
8
9
10
11
12
13
14
15
16
17
6
4
3
2
1 44 43 42 41 40
5
18
20 21 22 23 24 25 26 27 28
19
39
38
37
36
35
34
33
32
31
30
29
L9312AP
NC
LCF
RPWR
V
BAT1
V
BAT1
BGND
TIE B
′
TIE A
′
NC
NC
BGND
C
V
P
O
V
R
L
V
C
A
R
R
V
C
TXI
ITR
AGND
NC
DGND
V
DD
LATCH
RESET
B0
NC
VTX
N
R
R
P
P
T
N
D
B
B
R