Communication ICs PCM codec IC for digital cellular telephones BU8731KV 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. Applications Digital 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). Absolute maximum ratings (Ta = 25C) 610 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. Communication ICs BU8731KV Recommended operating conditions (Ta = 25C) Block diagram 611 Communication ICs Pin descriptions 612 BU8731KV Communication ICs BU8731KV 613 Communication ICs BU8731KV Electrical characteristics (unless otherwise noted, Ta = 25C, DVDD = RXVDD = TXVDD = 3.0V, FSYNC = 8kHz) 614 Communication ICs BU8731KV Electrical characteristics (unless otherwise noted, Ta = 25C, DVDD = RXVDD = TXVDD = 3.0V, FSYNC = 8kHz, FElectrical characteristics (gain of each attenuator = 0dB) 615 Communication ICs 616 BU8731KV Communication ICs BU8731KV 617 Communication ICs Digital AC characteristics 618 BU8731KV Communication ICs BU8731KV Measurement circuit 619 Communication ICs External dimensions (Units: mm) 620 BU8731KV