March 2000
PBL 386 30/2
Subscriber Line
Interface Circuit
Description
The PBL 386 30/2 Subscriber Line Interface Circuit (SLIC) is a 90 V bipolar integrated
circuit for use in Digital Loop Carrier, FITL and other telecommunications equipment.
The PBL 386 30/2 has been optimized for low total line interface cost and a high
degree of flexibility in different applications.
The PBL 386 30/2 emulates resistive loop feed, programmable between 2x50
Ω
and 2x900
Ω,
with short loop current limiting adjustable to max 45 mA. In the current
limited region the loop feed is nearly constant current with a slight slope
corresponding to 2x30kΩ.
A second lower battery voltage may be connected to the device to reduce short
loop power dissipation. The SLIC automatically switches between the two battery
supply voltages without need for external components or external control.
The SLIC incorporates loop current and ring trip detection functions.
The PBL 386 30/2 is compatible with loop start signaling.
Two- to four-wire and four- to two-wire voice frequency (VF) signal conversion is
accomplished by the SLIC in conjunction with either a conventional CODEC/filter or
with a programmable CODEC/filter, e.g. SLAC, SiCoFi, Combo II. The programmable
two-wire impendance, complex or real, is set by a simple external network.
Longitudinal voltages are suppressed by a feedback loop in the SLIC and the
longitudinal balance specifications meet the DLC requirements.
The PBL 386 30/2 package options are 24-pin SSOP, 24-pin SOIC and
28-pin PLCC.
Key Features
• 24-pin SSOP package
• High and low battery supply with
automatic switching
• 65 mW on-hook power dissipation in
active state
• On-hook transmission
• Long loop battery feed tracks Vbat for
maximum line voltage
• Only +5 V feed in addition to battery
• Selectable transmit gain (1x or 0.5x)
• No power-up sequence
• Programmable signal headroom
• 43V open loop voltage @ -48V battery
feed
• Constant loop voltage for line leakage
<5 mA (RLeak ~ >10 kΩ @ -48V)
• Full longitudinal current capability
during on-hook state
• Analog over temperature protection
permits transmission while the
protection circuit is active
• Integrated Ring Relay Driver
Ring Relay
Driver
RRLY
• -40°C to +85°C ambient temperature
range
DT
DR
TIPX
RINGX
HP
Ring Trip
Comparator
Input
Decoder
and
Control
C1
C2
DET
Two-wire
Interface
PLC
LP
PLD
REF
VTX
P
VCC
VBAT2
VBAT
Off-hook
Detector
AGND
BGND
VF Signal
Transmission
38
PBL
6 30
/2
RSN
PTG
24-pin SOIC, 24-pin SSOP, 28-pin PLCC
Figure 1. Block diagram.
1
38 PB
63 L
0/
2
Line Feed
Controller
and
Longitudinal
Signal
Suppression
POV
B
L
PSG
38
6
30
/2
ERICSSON [ ERICSSON ]
