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
• Low cost
• Few external components
• Programmable, constant current loop
feed
• Line feed characteristics independent
of battery supply variations
• -24 V to -58 V battery supply voltage
range
• Detectors
– programmable loop current detector
– ring trip detector
• Ring relay driver
• Hybrid function with conventional or
programmable CODEC/filters
• 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
• Idle noise typ. -83 dBmp, typ. 7 dBrnC
• Low on-hook power dissipation:
20 mW @ -28 V, 35 mW @ -48 V
• Tip-ring open circuit state for
subscriber loop power denial
• 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
ERICSSON [ ERICSSON ]
