PBL 387 71/1
Subscriber Line
Interface Circuit (SLIC)
Key Features
• On-chip ringing generation
- Balanced, up to 81 V
Peak
- Any waveform
- 5REN ringing load
- Automatic gain control of ring signal (AGC-R)
- Short circuit safe
• Low on-hook power consumption in Active
State (65 mW @ V
Bat
= -80 V)
• Automatic current controlled battery
switching between on-hook battery (V
Bat
) and
talk battery (V
TBat
)
• Pulse metering and on-hook transmission
• UL-1950 and MTU compliant on-hook line
voltage
• 3.3 V compatible logic interface
• Programmable Ring-Trip current
VTB
Ringing
Control
CRING
VR
VTBAT
VBAT
BGND
Ring Trip
Detector
VCC
AGND
PRT
C1
C2
Input
Decoder and
Control
TIPX
HP
C3
DET
RINGX
Two-wire
Interface
Line Feed
Controller
PLC
LP
REF
and
Longitudinal
Signal
Suppression
Off-hook
Detector
PLD
VTX
RSN
VF Signal
Transmission
Figure 1. Block diagram.
Description
The ringing FlexiSLIC™ PBL 387 71/1 Subscriber Line
Interface Circuit (SLIC) is a 90 V bipolar integrated cir-
cuit for use in short loop applications. The PBL 387 71/1
SLIC has been optimized for low power consumption,
low total line interface cost and for a high degree of
flexibility in various applications.
The PBL 387 71/1 SLIC supplies a balanced, sinewave
or trapezoidal ringing signal of up to 81 V
Peak
(85 V
DC supply) to the subscriber line across a load of up
to 5REN. The PBL 387 71/1 supplies programmable
constant current to the subscriber loop, sourced from
the talk battery. The On-Hook line voltage of 43 V to
56 V is derived from the battery. All battery switching
is internal to the device and is automatic. To further
reduce power consumption the automatic gain control
for the ring signal (AGC-R) keeps the level always
adjusted to the maximum, that can be sourced from the
available battery.
The SLIC incorporates loop current, ground key and
ring-trip detection functions. The PBL 387 71/1 is
compatible with loop start and ground start signal-
ling. Two- to four-wire and four- to two-wire voice
frequency (vf) signal conversion is accomplished by
the SLIC in conjunction with a standard codec. The
line terminating impedance and balance impedance
is programmable and may be complex or real for
worldwide compliance.
Longitudinal balance specifications and other device
characteristics are in compliance with Telcordia (Bell-
core) and ITU-T requirements.
Tip and ring voltages are UL-1950 compliant;
i.e. no two-wire line voltage exceeds 56 V. The
PBL 387 71/1 SLIC is packaged in a surface mount
28-pin SOIC package.
ERICSSON [ ERICSSON ]
