USB Host Audio Decoder ICs for USB/SD Audio Players

ROHM has recently announced the development of USB host audio decoder ICs compatible a variety of audio compression formats (BU9457KV: MP3, BU9458KV: MP3, WMA, AAC) and featuring high ESD resistance, making them suitable for car audio applications requiring excellent surge characteristics as well as home and portable audio sets.

USB and SD memory audio players are progressively supplanting CDs as the preferred choice to store and play back audio files due to their ease of use, high-speed writing capability, and superior compactness, which allows for greater portability. Demand is only expected to increase in the foreseeable future. To meet this need ROHM offers a lineup of compact, monolithic USB host audio ICs that support a variety of file formats. However, until now there were no decoder ICs that integrate protection circuits designed to prevent malfunction due to noise from the effects of wiring and nearby devices. Previously, external countermeasures, such as terminal protection ICs and surge protection diodes and resistors, have been necessary, especially in applications exposed to harsh operating environments (i.e. car audio). The BU9457KV and BU9458KV fulfill these requirements by integrating an improved communication error recovery circuit in the USB interface block and provide high ESD resistance (6kV at USB terminal/15kV air/8kV contact discharge) – meeting the requirements of the Electrostatic Discharge Immunity Test IEC 61000-4-2 Level 4 Standard. As a result, terminal protection ICs are no longer required, contributing to simpler designs and greater compactness.

In addition, incorporating interface hardware such as USB host and SD memory controllers, along with a D/A converter, sampling rate converter, compressed audio file decoder, file system, and system controller in a compact VQFP64 package (12mm×12mm) makes it possible to play back music from USB memory and SD memory cards using a single chip. This facilitates compact application designs and allows simple command control (i.e. play, stop, fast forward, rewind) without the need for a microcontroller, enabling configuration of a USB host audio system by simply adding the chip to existing sets.
The combination of additional functionality and protective countermeasures makes the BU9457KV and BU9458KV ideal for a wide variety of sets, including devices that did not previously support audio output, such as massage chairs and alarm clocks, as well as applications requiring high reliability (e.g. car audio).

Price :	2,000yen/unit
Availability :	July 2009 (Samples), October 2009 (OEM quantities)

USB Host Audio Decoder ICs 「BU9457KV」，「BU9458KV」(PDF：235KB)

■Key Features of BU9457KV and BU9458KV:

1. Built-in interface hardware, decoder, file system and system controller allow music playback from USB flash
   memory or SD memory cards
2. 6kV USB terminal ESD resistance
3. Superior surge resistance: 15kV (air discharge), 8kV (contact discharge).
4. Compact VQFP64 package (chip size: 12mm×12mm).
5. The BU9457KV and BU9458KV are both pin- and control-software-compatible, simplifying upgrade

■主な仕様

Part No.

Power Supply Voltage (V) (I/O)

USB Support

SD Support

Serial Interface

Display Data

MP3 Support

WMA Support

AAC Support

Audio Output

USB Terminal ESD Resistance

Discharge Resistance

Analog

Digital

Air

Contact

BU9457KV

3.0 to 3.6

USB2.0 Full Speed

MMC SD MiniSD MicroSD SDHC

I2C

Folder number, file number, playback time, folder name, file name, tag information (artist, album, title)

MPEG1, 2, 2.5 LAYER1, 2, 3

-

-

Line

I2S SPDIF

6KV

15KV

8KV

BU9458KV

WMA9 Standard

MPEG4 AAC-LC

■External Dimensions (VQFP64 Package)

■Terminology

• ESD Resistance
  ESD (Electro Static Discharge) resistance signifies the amount of static electricity, measured in volts, the component can withstand before breakdown/failure. Electrostatic voltage can be transmitted through the air (when the charged body is in close proximity to the device) or via direct contact, normally with a person.
• IEC 61000-4-2 level 4 standard
  A transient immunity standard that gauges the strength of electronic circuits against electrostatic discharge (ESD). Established by the IEC (International Electrotechnical Commission).
• WMA, AAC
  WMA is an abbreviation for Windows Media Audio, while AAC is short for Advanced Audio Coding. Both are types of audio compression formats.
  ※Windows Media™ is a registered trademark of Microsoft Corporation in the US and other countries.
  

USB Host Audio Decoder ICs