audio/videoZONE Products for the week of April 7, 2003

AKM Semiconductor Says . . .
AK4358: 8-Channel DAC Supports SACD, DSD & DVD 192-kHz 24-bit Formats
Single-chip enables "universal" audio disc players

Asahi Kasei Microsystems Semiconductor, Inc. (AKM), a leading supplier of audio ICs for professional and consumer markets introduced the AK4358, an 8-channel D/A converter compatible with both the SACD DSD format and DVD-Audio 24-bit, 192 kHz sampling format. The AK4358 delivers superior cost value for performance in DVD, SACD, AV receiver, and car audio applications.

The 8-channel, multi-format-compatibility AK4358 is based on AKM's previously-released AK4357, 6-channel DAC and offers a host of key features. These include reduced out-of-band noise achieved through the use of AKM's advanced multi-bit architecture and excellent anti-jitter performance from the switched capacitor DAC.

In order to minimize power consumption in today's multi-channel design, the AK4358 uses new low-power internal circuitry for a 12 percent improvement in power consumption efficiency, without adversely affecting audio performance.

Other key functions of the AK4358 are dedicated input ports for direct stream digital (DSD), which enables switching between PCM and DSD data. A built-in Low Pass Filter, specifically designed for DSD/SACD, enables "Scarlet Book" filter compliance to be easily achieved by adding a simple external analog filter.

The same output level is set for PCM data and DSD data so that digital volume and zero-detect functions work in the same way for both PCM and DSD data. This unifies playback levels without the need to be aware of what data format is being used.

EN-Genius Network Says...

The first things you notice about the AK4358 DAC over the previous AK4357 is that the number of output channels has been increased from 3 to 4 stereo channels and the numbers have improved, by a substantial 6 dB for the dynamic range/SNR to 112 dB, and by 4 dB for the THD+N to -94 dB. There is also an additional DSD input pair to increase the number to 3, in addition to the PCM inputs.

(DSD is one of those formats that Philips/Sony has not really marketed very well and most people think that it is a 192-kHz PCM-like datastream. It is, in fact, a 1-bit data rate at a sampling frequency of 2.822 MHz.)

A few more hidden improvements in the AK4358 are that it adds I2C control, 48 kHz/96 kHz TDM and programmability of the input channel of the DZF pin. What is not clear is if the independent channel control of digital de-emphasis is still retained.

Other features remain the same with sampling rates from 8 kHz to 192 kHz, 24-bit 8x digital filtering with a slow roll-off option, zero-detect function, channel-independent digital attenuators with soft transition, and soft mute.

AKM has listened to its customer base and leaps ahead in the universal receiver. The outputs continue to be full-differential SCF avaoiding ac-coupling capacitors.

The AK4358 is sampling in a LQFP-48 and is priced at $5.21 in 1000-piece lots. Evaluation boards are available.

Data Sheet