Multi-Channel DSD On a Chip

Last week, Asahi Kasei Microsystems Semiconductor (AKM), which supplies audio ICs for professional and consumer products, announced its line of Direct Stream Digital (DSD) Digital-to-Analog converters capable of supporting both Super Audio CD (SACD) Direct-Stream Bigital and 24-bit/192kHz LPCM DVD-Audio formats.

AKM says that the new chips include the AK4383, a two-channel DAC targeted towards high-end audiophile and professional applications, and the AK4357, which AKM says is the world's first six-channel DSD integrated circuit, targeted at multi-channel audio, including home theater and surround recording applications.

According to AKM, both chips include the company's 32-level multi-bit delta-sigma modulator and feature the "jitter tolerant" performance of AKM's switched-capacitor (SC) technology. The chips also feature direct balanced (differential) outputs, which the company says will "reduce implementation costs while increasing the performance for systems with excessive clock jitter, making the AK4383 and AK4357 ideal for audio DVD and SACD players, car audio, and electronic musical instruments."

Also included on the devices are a digital volume control, which, AKM claims, allows control of replay levels irrespective of the data format, and a "soft mute" function. According to the company, "This feature allows for changing the input streams without stopping the signal transmission." AKM also claims a dynamic range of 106dB for the AK4357 and 112dB for the AK4383.

According to AKM, "Because DSD data has a wide signal band and [noise shaping] in the high band, a low-pass filter is needed to attenuate high-frequency noise. The AK4383 provides a built-in LPF dedicated to DSD data, enabling the filtering characteristics recommended by the SACD format Scarlet Book to be easily achieved by adding a simple external analog filter."