Revision 3.4

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Key Features

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Line/Speech circuit, DTMF dialer, FSK transmitter and

tone ringer on a 32-pin CMOS-IC

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Enhanced voice switching

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Background noise monitoring

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DTMF tone generator

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FSK Transmitter V.23, BELL202, V.21, BELL 103

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Ringer tone programmable

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Tx- and Rx-gain programmable

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Digital volume control of Rx signals

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DC characteristic programmable

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Dual softclipping in handset mode

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Tx-softclipping in handsfree mode

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Common monitor amplifier for loudhearing, handsfree

and ringing

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Supply voltage generation for external circuitry

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Automatic line loss compensation (LLC)

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Real and complex impedance selectable by external

components

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Side tone adaptation selectable by external components

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Unique EMC performance

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Operating range from 15mA to 100mA (down to 5mA

with reduced performance)

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Few external components

General Description

AS2522 is a CMOS integrated circuit that incorporates DC

and AC line adaptation (DC-mask and synthesized AC-

impedance of 100

0Ω) as well as a speech circuit with

softclipping, line loss compensation and Rx-volume control

for handset and handsfree operation. It shall act as an a/b-

line powered device, which is controlled by a CPU via a

serial interface. Furthermore the AS2522 incorporates a

DTMF, FSK transmitter, single tone and ringer tone

generator.

AS2522 allows to use an off-the-shelf microprocessor

without special blocks and functions for telephone

applications. DTMF, FSK transmitter, single tone and ringer

tone generator can be controlled via the serial interface as

well as the gain settings in handset and handsfree mode.

Applications

Enhanced handsfree feature phones with CallerID and

extended displays.

Package

Available in 32-pin TQFP

Block Diagram

Telephone Line Interface and

Speakerphone Circuit

AS2522B

DATA SHEET