Product Brief AS3521B
Advanced Audio Decoder
Hardware Interfaces
General Description
The chip is a fully integrated and highly flexible digital audio
decoder for the austriamicrosystems mobile music platform.
Main purpose of this platform is the integration of digital
audio decoder (MP3, AAC and other formats as future
option), micro controller unit, data interfaces and the analog
audio channels for reproduction of digital audio.
This codec-chip contains a high performance 18 bit digital
to analog converter. The dynamic range exceeds 95dB for
best audio quality, for multi media applications (audio
playback) within battery or line operated equipment.
An additional audio power amplifier can directly drive
external headphones or small 4Ω speakers with a power of
up to half a watt. The power-up is click- and pop-less due to
a smooth start-up circuitry. The overall distortion level is
always below 0.02%.
USB Interface version 1.1 (support of MSC)
MultiMediaCard / Secure Digital Card Interface
(support of MMC mode)
Smart Media Card Interface
NAND Flash Interface
I 2 C Slave Interface (for access to control registers)
SPI (master or slave)
General Purpose I/O Lines (40)
On chip DCDC Converter
1.0 to 5.5V input voltage range
4 On-chip high performance voltage regulators
Digital Supply, 2.9V
Analog Supply, 2,9V
Core Supply, 2.25V
USB Transceiver Supply, 3.2V
18 Bit stereo DAC
The microphone input amplifier contains an automatic gain
control (AGC) with a dynamic range of 40dB to generate an
amplified and compressed signal for the ADC, which
provides 14 Bit resolution at 8kHz sampling-rate.
Dynamic range typ. 93 dB
THD typ. -85dB
De-emphasis for 32 kHz, 44.1 kHz and 48 kHz
Furthermore all necessary power management is included
such as bandgap reference and three voltage regulators.
The two 2.9V regulators are used internally (analog and
digital supply), but can also be used for external purposes
as well. The third output is designed to supply the digital
core, and is programmable to either 2.25V or 2.5V. The
performance of the regulators is excellent (noise, line- and
load-regulation) and allows the direct supply of sensitive
analog circuits.
Max. 2x 0.5W @ 4Ω
Analog volume control –39dB to +3dB, 3dB steps
including mute)
Click- and pop-less startup and power down
Auxiliary inputs for additional audio sources
Because of the internal supply and signal filtering only few
small external capacitors are required for de-coupling and
stabilising and lead to very low output noise.
The current consumption is very low and makes the chip
ideally for battery powered devices.
Key Features
Embedded 32-Bit RISC Controller
Stereo power audio amplifier
Microphone input
14 Bit Σ∆−ADC mono
24kHz FM-quality recording
Automatic gain control (AGC)
Audio Formats: general platform for popular digital
audio formats: MP3, AAC, WMA and others.
Audio sampling rates: 8, 11.025, 12, 16, 22.05, 24, 32,
44.1, and 48 kHz
Wide battery supply range 1.0V – 5.5V
12.288MHz crystal or 13MHz clock input
System Power Management Features
Low power consumption
MCU and DSP functionality
Scaleable architecture
User accessible controller/DSP/memory resources
Boot ROM
Audio platform for cellular phones
Clock speed: 16 - 65 MHz
Stand alone MP3 player and PDAs
CD and DVD player
1.11, Feb. 2005
Page 1 of 3
Product Brief AS3521B
Block Diagram
Fla Dat
sh a
> ||
Figure 1
1.11, Feb. 2005
Block Diagram of AS3521
Page 2 of 3
Product Brief AS3521B
Copyright © 1997- 2005, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe. Trademarks
Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used
without the prior written consent of the copyright owner.
Devices sold by austriamicrosystems AG are covered by the warranty and patent identification provisions appearing in its Term
of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set
forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems AG reserves the
right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system,
it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal
commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high
reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended
without additional processing by austriamicrosystems AG for each application.
The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However,
austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to personal
injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential
damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No
obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG rendering of technical or
other services.
Contact Information
austriamicrosystems AG
Business Unit Communications
A 8141 Schloss Premstätten, Austria
T. +43 (0) 3136 500 0
F. +43 (0) 3136 5692
[email protected]
For Sales Offices, Distributors and Representatives, please visit:
1.11, Feb. 2005
Page 3 of 3