STAC9704 Datasheet, PDF (6/49 Pages) Hynix Semiconductor – Multimedia Audio Codec for AC97

SigmaTel, Inc.
STAC9704/7
AC-link
SYNC
BIT_CLK
SDATA_OUT
SDATA_IN
RESET
Power
Management
Digital
Interface
Registers
64 x 16 bits
Figure 2. STAC9704 Block Diagram
4 stereo
sources
2 mono sources
mono
stereo
PCM out DACs
48Kss
DAC
DAC
MIXER
LNLVL_OUT
LINE_OUT
MONO_OUT
Analog mixing
PCM in ADCs
ADC
ADC
and
Gain control
Mic
MIC1
M
Boost
U
0/20 dB
X
MIC2
48Kss
The STAC9704/7 block diagram, above, illustrates its primary functional blocks. It performs fixed 48K sample
rate D-A & A-D conversion, mixing, and analog processing. The digital interface communicates with the AC’97
controller via the five wire AC-link and contains the 64 word by 16-bit registers. Two fixed 48Kss DAC’s
support a stereo PCM-out channel which contains a mix generated in the AC’97 controller of all software sources,
including the internal synthesizer and any other digital sources. The Mixer block mixes the PCM-out with any
analog sources, then outputs to LINE_OUT and LNLVL_OUT. The MONO_OUT delivers either mic only or a
mono mix of sources from the mixer. The two fixed 48Ks ADC’s take any mix of mono or stereo sources, and
convert it to a stereo PCM-in signal. All ADCs and DACs operate at 18-bit resolution.
The STAC9704/7 is designed primarily to support stereo, 2-speaker PC audio. However, multi-channel encoded
stereo can be played out through the LINE_OUT and LNLVL_OUT. This encoded signal can be played on
normal stereo speakers, or sent to consumer equipment or other decoding devices via LINE_OUT and
LNLVL_OUT to an analog input connection for multi-channel playback. As an option, the STAC9704/07
provides for a stereo enhancement feature, Sigmatel Surround 3D (SS3D). SS3D provides the listener with
several options to expand the soundstage beyond the normal 2-speaker arrangement.
Together with the logic component (controller) of AC’97, STAC9704/7 can be SoundBlaster^® and Windows^®
Sound System compatible. SoundBlaster^® is a registered trademark of Creative Labs. Windows^® is a registered
trademark of Microsoft Corporation.
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10/02/98