DATA SHEET
MAS 35x9F
MPEG Layer 2/3, AAC Audio Decoder,
G.729 Annex A Codec
In MPEG 1 (ISO 11172-3), three hierarchical layers of
compression have been standardized. The most
sophisticated and complex, layer 3, allows compres-
sion rates of approximately 12:1 for mono and stereo
signals while still maintaining CD audio quality. Layer 2
(widely used, e.g., in DVD) achieves a compression of
8:1 without significant losses in audio quality.
Release Note: Revision bars indicate significant
changes to the previous edition. This data sheet
applies to the MAS 35x9F version B4.
1. Introduction
The MAS 35x9F supports the “Advanced Audio Cod-
ing” (AAC) that is defined as a part of MPEG 2. AAC
provides compression rates up to 16:1. It defines sev-
eral profiles for different applications. This IC decodes
the “low complexity profile” that is especially optimized
for portable applications.
The MAS 35x9F is a single-chip, low-power MPEG
layer 2/3 and MPEG2-AAC audio stereo decoder. It
also contains the G.729 Annex A speech compression
and decompression technology for use in memory-
based or broadcast applications. Additional functional-
ity is achievable via download software (e.g., CELP
voice decoder, Micronas SC4 (ADPCM) encoder/
decoder).
The MAS 35x9F also implements a voice encoder and
decoder that is compliant to the ITU Standard G.729
Annex A.
The MAS 35x9F decoding block accepts compressed
digital data streams as serial bit streams or in parallel
format, and provides serial PCM and S/PDIF output of
decompressed audio. In addition to the signal process-
ing function, the IC incorporates a high-performance
stereo D/A converter, headphone amplifiers, a stereo
A/D converter, a microphone amplifier, and two DC/DC
converters.
SC4 is a proprietary Micronas speech codec technol-
ogy that can be downloaded to the MAS 35x9F, to
allow recording and playing back speech at various
sampling rates.
Thus, the MAS 35x9F provides a true “all-in-one”
solution that is ideally suited for highly optimized mem-
ory-based portable music players with integrated
speech recording and playback function.
Micronas
June 30, 2004; 6251-505-1DS
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MICRONAS [ MICRONAS ]
