L7554 Low-Power SLIC
Data Sheet
March 1997
Pin Information
I
PROG
FB2
6
7
V
CC
RCVP
RCVN
TXI
LCTH
V
REG
DCOUT
V
BAT
PR
8
9
10
11
12
13
14
15
16
17
18
CF2
5
4
3
2
1
44
43
42
41
40
39
38
37
36
35
FB1
SN
XMT
B1
B2
NLC
NRDET
RTSP
RTSN
PT
VTX
L7554
34
33
32
31
30
29
19
CF1
20
VITR
21
I
CM
22
R
GDET
23
B0
24
AGND
25
AGND
26
DCR
27
BGND
28
12-2571 (C)
Figure 2. Pin Diagram (PLCC Chip)
Table 1. Pin Descriptions
Pin
3
8
9
10
11
12
13
14
15
16
18
19
Symbol Type
I
PROG
V
CC
RCVP
RCVN
TXI
LCTH
V
REG
DCOUT
V
BAT
PR
CF2
CF1
I
—
I
I
—
I
I
O
—
I/O
—
—
Description
Current-Limit Program Input.
A resistor to DCOUT sets the dc current limit of the
device.
+5 V Power Supply.
Receive ac Signal Input (Noninverting).
This high-impedance input controls the ac
differential voltage on Tip and Ring.
Receive ac Signal Input (Inverting).
This high-impedance input controls the ac differen-
tial voltage on Tip and Ring.
ac/dc Separation.
Connect a 0.1
µF
capacitor from this pin to VTX.
Loop Closure Threshold Input.
Connect a resistor to DCOUT to set off-hook threshold.
Regulated Negative dc Battery Voltage.
Can be connected to an external regulator.
Otherwise, connect to V
BAT
.
dc Output Voltage.
This output is a voltage that is directly proportional to the absolute
value of the differential Tip/Ring current.
Battery Supply.
Negative high-voltage power supply.
Protected Ring.
The output of the ring driver amplifier and input to loop sensing circuitry.
Connect to loop through overvoltage protection.
Filter Capacitor 2.
Connect a 0.1
µF
capacitor from this pin to AGND.
Filter Capacitor 1.
Connect a 0.47
µF
capacitor from this pin to pin CF2.
4
Lucent Technologies Inc.
AGERE [ AGERE SYSTEMS ]
