September 1997
PBL 3766, PBL 3766/6
Subscriber Line
Interface Circuit
Description
The PBL 3766 Subscriber Line Interface Circuit (SLIC) is a monolithic integrated
circuit, manufactured in 75 V bipolar technology. The PBL 3766 SLIC facilitates the
design of cost effective, high performance on-premises (ONS) analog line interface
cards for PABX systems and terminal adapters. Small package size and few
required external components result in a miniaturized design.
The PBL 3766 programmable, constant current loop feed system can operate with
battery supply voltages between -24 V and -58 V.
The SLIC incorporates loop current and ring trip detection functions as well as a
ring relay driver.
The two- to four-wire and four- to two-wire voice frequency (vf) signal conversion,
i.e. the hybrid function, is provided by the SLIC in conjunction with either a conven-
tional or a programmable CODEC/filter.
The PBL 3766 package is a 22 pin, plastic dual-in-line (batwing) or a 28-pin, plastic
j-leaded chip carrier (PLCC).
The differences between PBL 3766 and PBL 3766/6 are the specifications for
balance, output offset voltage, and insertion loss.
Key Features
鈥?Low cost
鈥?Few external components
鈥?Programmable, constant current loop
feed
鈥?Line feed characteristics independent
of battery supply variations
鈥?-24 V to -58 V battery supply voltage
range
鈥?Detectors
鈥?programmable loop current detector
鈥?ring trip detector
鈥?Ring relay driver
鈥?Hybrid function with conventional or
programmable CODEC/filters
鈥?Line terminating impedance, complex
or real, set by a simple external
network or controlled by a
programmable CODEC/filter
Ring Relay
Driver
5/3
RINGRLY
鈥?Idle noise typ. -83 dBmp, typ. 7 dBrnC
鈥?Low on-hook power dissipation:
20 mW @ -28 V, 35 mW @ -48 V
鈥?Tip-ring open circuit state for
subscriber loop power denial
鈥?On-hook transmission
13/10
DT
23/20
C1
C2
Ring Trip
Detector
Input/Output
Decoder and
Control
12/9
TIPX
HPT
HPR
RINGX
VCC
VEE
VBAT
GND
27/21
20/15
21/16
28/22
4/2
18/13
3, 6, 10, 17, 24/
5, 6, 17, 18
2/1
9/7
11/8
E0
DET
7/4
RSG
Loop Current
Detector
22/19
19/14
RD
VTX
P
L
B
P 66
37
16/12 RSN
VF Signal
Transmission
Figure 1. Block diagram. Pin numbers PLCC/DIP.
4-1
B
L
37
Two-wire
Interface
Line Feed
Controller
and
Longitudinal
Signal
Suppression
14/11 RDC
66