The BU8731KV is a PCM codec IC developed for use with digital cellular telephones. It contains analog input / output features such as a 14-bit linear precision, µ / A-LAW codec, mic and speaker amplifiers, and switching transistor for the ringer drive. This all makes the BU8731KV perfect for PDC and CDMA-type cellular telephones.

FEATUREs
1) -3V single power supply (VDD = 2.7V to 3.3V).
2) Built-in 14-bit precision linear, µ / A-LAW codec.
3) Transmission filter for the codec unit conforms to ITU-T recommendations.
4) Built-in PLL circuit for system clock generation.
5) Clock frequency for PCM data transmission can be set anywhere between 64kHz (128kHz when linear) to 2048kHz.
6) Analog input / output functions:
    • Built-in mic amplifier.
    • Built-in receiver speaker amplifier (32Ω BTL type).
    • Built-in earphone speaker amplifier (32Ω single type).
    • Built-in drive amplifier for reception REXT (600Ω).
    • Built-in electronic volume control for gain adjustment (for reception, transmission, and tone).
    • Data signal I / O circuit allows for connection to external devices.
    • For the REXT output and earphone output, softmute function reduces pop noise when the power is turned on and off.
7) DTMF signal and scale tone signal generator functions are built into the tone signal generator block.
8) Internal switching transistor for ringer drive.
9) VQFP 48-pin package.

APPLICATIONs
    Digital cellular telephones