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.
FApplications
Digital cellular telephones
FFeatures
1)
)3V
single power supply (V
DD
= 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:
S
Built-in mic amplifier.
S
Built-in receiver speaker amplifier (32Ω BTL type).
S
Built-in earphone speaker amplifier (32Ω single
type).
FAbsolute
maximum ratings (Ta = 25_C)
S
Built-in drive amplifier for reception REXT (600Ω).
S
Built-in electronic volume control for gain adjust-
ment (for reception, transmission, and tone).
S
Data signal I / O circuit allows for connection to ex-
ternal devices.
S
For the REXT output and earphone output, soft-
mute function reduces pop noise when the power
is turned on and off.
7) DTMF signal and scale tone signal generator func-
tions are built into the tone signal generator block.
8) Internal switching transistor for ringer drive.
9) VQFP 48-pin package.
610
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