UTC34018 Datasheet | Youwang

.. UTC34018 VOICE SWITCHED SPEAKERPHONE CIRCUIT DESCRIPTION LI NEAR I NTEGRATED CI RCUI T The UTC34018 speakerphone integrated circuit incorporates the necessary amplifier, attenuators, and control functions to produce a high quality hands-free speakerphone system. Included are a microphone amplifier, a power audio amplifier for the speaker, transmit and receive attenuators, a monitoring system for background sound level, and an attenuation control system which responds to the relative transmit and receive levels as well as the background level. Also included are all necessary regulated voltages for both internal and external circuitry, allowing lining powered operation(no additional power supplies required).A chip select pin allows the chip to be powered down when not in use. A volume control function may be implemented with an external potentiometer. The UTC34018 applications include speakerphones for household and business use, inter systems, automotive telephones, and others. DIP-28 Features - All necessary level detection and attenuation controls for a hand-free telephone in a single integrated circuit - Background noise level monitoring with long time constant - Wide operating dynamic range through signal pression - On-chip supply and reference voltage regulation - Typical 100mW output power(into 25 ohms)with peak limiting to minimize distortion - Chip Select pin for active/standby operation - Linear Volume control function - Standard 28-pin plastic DIP...