Applications

Description

The MSM7731 is an IC device developed for portable, handsfree communication with built-in line echo canceler, acoustic echo canceler, and transmission signal noise canceler. Built-in to the voice signal interface is a linear CODEC for the analog interface on the acoustic-side, and a linear CODEC for the analog interface on the line-side. On the line-side, in addition to the analog interface, there is also a µ-law PCM/16-bit linear digital interface. Equipped with gain and mute controls for data transmission and reception, a µ-law PCM/16-bit linear digital interface for memo recording and message output, and transfer clock and sync clock generators for digital communication, this device is ideally suited for a handsfree system.

Block Diagram

Features

»	Single 3 V Power Supply Operation (2.7 to 3.6 V)
»	Built-in 2-channel (line and acoustic) echo canceler »  Echo attenuation : 35 dB (typ.) for white noise Cancelable echo delay time : »  Line echo canceler + acoustic echo canceler : Tlined = 27 ms (max.) Tacoud = 59 ms – Tlined (max.) Acoustic echo canceler only : Tacoud = 59 ms (max.)
»	Built-in transmission signal noise canceler »  Noise attenuation : 17 dB (typ.) for white noise 40 dB (typ.) for single tone
»	Built-in 2-channel CODEC »  Synchronous transmission and reception enables full duplex operation
»	Built-in analog input gain amp stage (max. gain = 30 dB)
»	Analog output configuration: Push-pull drive (can drive a 1.2 k load)
»	Built-in transmit slope filter
»	Digital interface coding formats: µ-law PCM, 16-bit linear (2's complement)
»	Digital interface sync formats: Normal-sync, short-frame-sync
»	Built-in digital transmission clock generators »  Sync clock (SYNC): 8 kHz output »  Transmission clock (BCLK): 64 kHz output (µ-law PCM) / 128 kHz output (16-bit linear)
»	Digital transmission rate »  External input: 64 kbps to 2048 kbps »  Internal generation: 64 kbps (µ-law PCM)/128 kbps (16-bit linear)
»	Fixed digital interface sync clock (SYNC) enables automatic power-down
»	Master clock frequency: 19.2 MHz Compatible with crystal oscillator and crystal
»	Low power consumption »  Operating mode: typ. 35 mW (when VDD = 3.0 V in a silent mode) »  Power-down mode: typ. 0.02 mW (when VDD = 3.0 V in a silent mode)
»	Control by both the serial microcomputer interface and parallel port is possible
»	Transmit / receive mute function, transmit/receive programmable gain setting
»	Package: 64-pin plastic QFP (QFP64-P-1414-0.80-BK) (Product name: MSM7731-02GA)