ROHM developed the D/A converter IC (DAC chip) BD34352EKV and the corresponding evaluation board BD34352EKV-EVK-001 – supporting the playback of high-resolution sound sources in high fidelity audio equipment.
Designed to maximally extract and convert high resolution digital audio data to analog audio signals, audio DAC chips are one of the most important components for determining the quality in audio equipment.
Leveraging 50 years of expertise in developing audio ICs allowed ROHM to establish ‘sound quality design technology’ – capable of extracting the full amount of information from sound sources and offer products that deliver superior sound quality, including sound processor and power management ICs.
Among these is the BD34301EKV, the flagship DAC chip of ROHM’s MUS-IC series, which has been highly evaluated for its sound quality since its release in February 2021. It continues to see worldwide adoption. However, to meet the growing demand from manufacturers for a DAC chip that can be used in a wider range of audio equipment, ROHM developed the BD34352EKV.
The new DAC chip BD34352EKV is specially tuned to powerfully express the energy of sound sources while maintaining the natural flat sound characteristics of ROHM’s DAC chips design concept. At the same time, an advanced digital filter is included – the same as for BD34301EKV. That leads to superior numerical performance (S/N ratio: 126dB, THD+N: -112dB) of the DAC chip, making it ideal for high-end audio equipment. In addition, the BD34352EKV features pin compatibility with the BD34301EKV. It has the same customizable filter as the BD34301EKV. This enables different sound quality tunings for each audio device – reducing development load while contributing to the creation of ideal sound sought by audio manufacturers.
Developed as a DAC chip for high-end audio equipment, the BD34352EKV not only maintains the natural flat sound characteristics of ROHM’s DAC chips design concept. It is also specially tuned to express the energy of sound sources more powerfully than the BD34301EKV, which emphasizes quietness and spatial reverberation.
To achieve the desired sound, the BD34352EKV provides the following features by leveraging sound quality design technology cultivated from identifying 28 parameters related to sound quality.
Achieves the demanded numerical and sound quality performance of DAC chips for high-end models
The BD34352EKV achieves excellent numerical performance (S/N ratio: 126dB, THD+N: -112dB) while also improving sound quality in ways that cannot be defined by simple numerical values. For example, in the D/A conversion circuit consisting of current segments, the output current has been adjusted by adopting circuit technology used in the BD34301EKV. At the same time, the digital filter (FIR filter), a key function of the digital signal processing circuit, is designed to faithfully process even the smallest signals by achieving a rejection band attenuation of -150dB or less (a performance indicator of digital filters). This makes it possible to extract the full range of information from sound sources. It provides sound quality characteristics that allow listeners to hear more powerful, natural flat sound.
Customizable digital filter allows designers to tailor the sound to audio equipment
The BD34352EKV enables customization of the digital filter (FIR filter) in the digital signal processing circuit which affects sound quality. Preset, custom, or external settings can be selected. Even the filter’s calculation coefficients and oversampling rate can be programmatically customized. As a result, it not only features pin compatibility but also has the same customizable filter as the BD34301EKV. That allows to achieve different sound quality tunings for each device. Overall, this reduces development load while contributing to the creation of ideal sound sought by audio manufacturers.