ROHM's New High Resolution Audio SoC Supports a Variety of Sound Sources

Optimized design with built-in memory improves performance while contributing to greater miniaturization


ROHM has recently announced the availability of a high resolution audio SoC designed to act as the ‘brain' in audio applications such as Bluetooth speakers, USB DACs, and mini/micro component systems by carrying out control and management of peripheral components and input/output I/F as well as enable playback of a wide range of audio sources.

In recent years, a variety of audio devices are required to faithfully reproduce information from different sound sources (media/music files) – not just high-resolution audio. However, in order to support a wide range of audio sources multiple media decoders are required (i.e. CD, USB, Bluetooth) along with additional peripheral components, leading to challenges relating to increased software complexity and development load.

For the audio sector ROHM not only offers general-purpose ICs such as opamps, but audio-related ICs as well, ranging from media decoders and speaker amps to sound processors. This time, ROHM developed an audio SoC that acts as the ‘brain' of audio devices along with a reference design that improves audio quality for the entire system while minimizing development load.

Audio SOC Application Block Diagram

The BM94803AEKU integrates a processor chip with SDRAM featuring an optimized architecture that leverages software and circuit elements such as ASIC (Application Specific IC), MCU, and various media decoders (developed by the ROHM Group) on a single chip. The media decoder supports a wide range of audio sources, and utilizing over 20 years of expertise allows ROHM to ensure stable playback of damaged CDs and even non-standard USB. In addition, SDRAM is built in that contributes to greater miniaturization.

This SoC allowed ROHM to achieve the industry's first high-resolution reference audio design. The design maximizes the performance of audio devices and peripheral applications by configuring ROHM's amp, CD driver, and other elements around the audio SoC. Furthermore, providing dedicated software enables rapid development of audio devices capable of stable playback of a wide range of audio sources, shortening development time considerably.

Key Features

SmartphoneAOA2.0 (Android) iAP1/iAP2 (iOS)
PCAudio Class2.0 (USB-DAC)

1. Compatible with a broad range of audio formats
The BM94803AEKU supports a variety of media, from conventional (CD, USB, SD) to newer protocols (smartphones, Bluetooth), while at the same time covering a range of music formats, including FLAC and DSD.

2. Ensures smooth playback
Expertise cultivated for over 20 years in developing media decoders ensures smooth playback without skipping, even with CDs featuring surface scratches. Non-standard USB memory prevalent in emerging countries can also be read, while unmatched playback stability allows ROHM to meet customer expectations for audio equipment.

3. Full software suite supports audio device development
Providing an audio SoC optimized for audio devices along with a reference design that includes dedicated software for maximizing performance significantly reduces development load required by audio equipment makers, speeding up development and shortening time-to-market considerably.

4. Built-in CD DSP and SDRAM contribute to greater miniaturization
ROHM's audio SoC integrates both a CD DSP (CD media decoder) and 16Mb SDRAM (LAPIS Semiconductor product), which were previously implemented separately, in a single package. This not only reduces mounting area, but also eliminates the need to consider radiation noise between components.

Reference Audio Design
This reference design maximizes the performance of ROHM audio devices, in particular the new audio SoC. Besides audio components, peripheral applications such as a tuner module, Bluetooth module, and CD driver are built in, making it possible to immediately verify playback operation and enable quick development of high-resolution audio equipment.

Reference Design Board


  • Hi-fi audio equipment
  • High resolution component systems
  • Bluetooth speakers


High Resolution Audio Source
General CD quality audio sources are played back at a sampling frequency of 44.1kHz and 16bit quantization bit rate, but with high resolution audio sources sampling frequencies 96kHz or more and 24bit quantization are common. In other words, the amount of information contained in high resolution audio sources is much greater, resulting in higher quality audio.

SoC (System on Chip)
Generally, an IC that integrates functions necessary for system operation. Here it represents a series of functions for enabling output by extracting audio signals from audio sources.

Notes on licensing and trademarks

*Introducing iPod/iPhone/iPad compatible products requires an MFi license (Made for iPod/iPhone/iPad). iPod and iPhone are registered trademarks of Apple, Inc. in the US and other countries. iPad is a trademark of Apple Inc.
*SD is a registered trademark of SD Association.
*Windows Media and Windows are registered trademarks of Microsoft Corp. in the US and other countries.