Description

The PBL 386 20/2 Subscriber Line Interface Circuit (SLIC) is a 90 V bipolar integrated

circuit for use in PBX,Terminal adapters and other telecommunications equipment.

The PBL 386 20/2 has been optimized for low total line interface cost and a high

degree of flexibility in different applications.

The PBL 386 20/2 has constant current feed, programmable to max. 30 mA.

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, ground key and ring trip detection functions.

The PBL 386 20/2 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 impedance, 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 Bellcore TR909 requirements.

The PBL 386 20/2 package options are 24-pin SSOP, 24-pin SOIC and 28 pin PLCC.

Figure 1. Block diagram.

June 1999

PBL 386 20/2

Subscriber Line

Interface Circuit

Key Features

• 24-pin SSOP package

• High and low battery with automatic

switching

• 60 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

• 44V open loop voltage @ -48V battery

feed

• Full longitudinal current capability

during on-hook state

• Analog over temperature protection

permits transmission while the

protection circuit is active

• Integrated Ring Relay driver

• Ground key detector

• Programmable signal headroom

24-pinSOIC, 24-pin SSOP, 28-pin PLCC

RRLY

C1

C2

C3

DET

PSG

REF

LP

PLD

PLC

VTX

RSN

PTG

BGND

AGND

VBAT

VBAT2

VCC

HP

RINGX

TIPX

DR

DT

Ring Relay

Driver

Input

Decoder

and

Control

Ring Trip

Comparator

Ground Key

Detector

Line Feed

Controller

and

Longitudinal

Signal

Suppression

Off-hook

Detector

VF Signal

Transmission

Two-wire

Interface

POV

1

PBL

386

20/2