GENERAL DESCRIPTION
The MSM7731 is an LSI 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 m-law PCM/16-bit linear digital interface.
Equipped with gain and mute controls for data transmission and reception, a m-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.

FEATURES
• Single 3 V power supply operation (2.7 V to 3.6 V)
• Built-in 2-channel (line and acoustic) echo canceler
   Echo attenuation : 35 dB (typ.)
   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: 13 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 kW load)
• Built-in transmit slope filter
• Digital interface coding formats: m-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 (m-law PCM)/128 kHz output (16-bit linear)
• Digital transmission rate
   External input: 64 kbps to 2048 kbps
   Internal generation: 64 kbps (m-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. 105mW (when VDD = 3.0 V)
   Power-down mode: typ. 0.3mW (when VDD = 3.0 V)
• 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: MSM7731-01GA)