L9214G - Agere Systems, Inc.

Product Brief

June 2000

L9214A/G

Low-Cost Ringing SLIC

Introduction

The L9214 is a subscriber line interface circuit that is

optimized to provide a very low-cost solution for

short- and medium-loop applications. This device

provides the complete set of line interface functional-

ity, including power ringing needed to interface to a

subscriber loop. This device has the capability to

operate with a VCC supply of 3.3 V or 5 V and is

designed to minimize external components required

at all device interfaces.

Features

■Low-cost solution

■Onboard ringing generation with software adjust-

able crest factor switching

■Flexible VCC options

— 3.3 V or 5 V VCC

— No –5 V required

■Power control options

— Power control resistor

— Automatic battery switch to minimize off-hook

power

■Eight operating states

— Scan mode for minimal power dissipation

— Forward and reverse battery active

— On-hook transmission states

— Ring mode

— Disconnect mode

■Low on-hook power

— 25 mW scan mode

— 165 mW active mode

■Two SLIC gain options to minimize external com-

ponents in codec interface

■Loop start, ring trip, and ground key detectors

■Programmable current limit

■On-hook and scan mode line voltage clamp

■Thermal protection

■28-pin SOG and 32-pin PLCC packages

Applications

■Voice over Internet Protocol (VoIP)

■Cable Modems

■Terminal Adapters (TA)

■Wireless Local Loop (WLL)

■Network Termination (NT)

■PBX

■Key Systems

Description

This device is optimized to provide battery feed, ring-

ing, and supervision on short- and medium-loop plain

old telephone service (POTS) loops. Supported

round trip loop length is up to 1000 Ω.

This devi ce provides power ring to the subscriber b y

the use of line reversal to create either a sine wave

ringing signal with a PWM input or a trapezoidal ring-

ing signal with a selectable crest factor from a square

wave input. It provides forward and reverse battery

feed states, on-hook transmission, a low-power scan

state, and a forward disconnect state.

The device re quire s a VCC and line feed battery to

operate. VCC may be either a 3.3 V or a 5 V supply.

The ringing signal is derived from the high-voltage

battery. An automatic battery switch is included to

allow for use of a second lower voltage battery in the

off-hook mode, thus minimizing short-loop off-hook

power consumption and dissipation. If the user

desires single battery operation, a power resistor is

required to reduce the power dissipation in the SLIC.

Loop closure, ring trip, and ground key detectors are

available. The loop closure detector has a fixed

threshold with hysteresis. The ring trip detector and

ground key detector threshold and time constants are

externall y set.

The dc current limit is programmed by an external

resistor , the maximum current limit determined by the

Vcc supply.

The overhead volt age for this device is fixed and the

device is capable of supporting 3.17 dB into a 600 Ω

load with minimal overhead.

The device is offered with two gain options. This

allows for an optimized codec interface, with minimal

external components regardless of whether a first-

generation or a programmable third-generation

codec is used.

Lucent Technologies Inc. reserves the right to make changes to the product(s) or information contained herein without notice. No liability is assumed as a result of their use or application. No

rights under any patent accompany the sale of any such product(s) or information.

June 2000

PB00-024ALC

For additional information, contact your Microelectronics Group Account Manager or the following:

INTERNET: http://www.lucent.com/micro

E-MAIL: docmaster@micro.lucent.com

N. AMERICA:Microelectronics Group, Lucent Technologies Inc., 555 Union Boulevard, Room 30L-15P-BA, Allentown, PA 18109-3286

1-800-372-2447, FAX 610-712-4106 (In CANADA: 1-800-553-2448, FAX 610-712-4106)

ASIA PACIFIC:Microelectronics Group, Lucent Technologies Singapore Pte. Ltd., 77 Science Park Drive, #03-18 Cintech III, Singapore 118256

Tel. (65) 778 8833, FAX (65) 777 7495

CHINA: Microelectronics Group, Lucent Technologies (China) Co., Ltd., A-F2, 23/F, Zao Fong Universe Building, 1800 Zhong Shan Xi Road, Shanghai

200233 P. R. China Tel. (86) 21 6440 0468, ext. 325, FAX (86) 21 6440 0652

JAPAN: Microelectronics Group, Lucent Technologies Japan Ltd., 7-18, Higashi-Gotanda 2-chome, Shinagawa-ku, Tokyo 141, Japan

Tel. (81) 3 5421 1600, FAX (81) 3 5421 1700

EUROPE: Data Requests: MICROELECTRONICS GROUP DATALINE: Tel. (44) 7000 582 368, FAX (44) 1189 328 148

Technical Inquiries:GERMANY: (49) 89 95086 0 (Munich), UNITED KINGDOM: (44) 1344 865 900 (Ascot),

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ITALY: (39) 02 6608131 (Milan), SPAIN: (34) 1 807 1441 (Madrid)

Product Brief

June 2000

Low-Cost Ringing SLIC

L9214A/G

L9214 Architecture Diagram

12-3530.C (F)

IREF

VITR

TXI

ITR

VTX

ICM

TRGDET

CF2

CF1

FB2

FB1

POWER/BATTERY SWITCH

AGND VCC BGNDVBAT2 VBAT1 IPROG NSTAT RTFLT DCOUT

REFERENCE

AAC

X20

(ITR/308)

TIP/RING

CURRENT

SENSE

ITR

RFT

18 Ω

RFR

18 Ω

VBAT1PARALLEL

DATA

INTERFACE

B0 B1 B2 B3

RCVN

RCVP

CURRENT

LIMIT

AND

INRUSH

CONTROL

RING

LOOP

RECTIFIERVTX

COMMON-

MODE

CURRENT

DETECTOR

TRIP

CLOSURE

–

9214A GAIN = 4

–

GAIN

9214G GAIN = 1

ac INTERFACE

CIRCUIT

VBAT2

VBAT1VBAT2