Analog Devices, Inc. announced a 24-bit stereo audio DAC (digital-to-analog converter) that represents the industry's first standalone solution to enable OEMs to meet the new 192-kHz audio sample rate standard for DVD players. Designated the AD1853, the new IC combines proprietary data conversion technology with the industry's first multibit sigma-delta converter core to deliver significantly improved audio performance at every sample rate from 32 kHz to 192 kHz.

The DVD Forum, which includes leading companies such as Toshiba, Pioneer, Warner Bros. and Matsushita, has announced its new DVD Audio Specification v1.0 for next- generation DVD machines. The advanced 192-kHz sample rate capability is expected to be initially incorporated into the highest performance category of consumer DVD players, followed by the adoption of the new standard in all DVD players, and PC players targeted for the digital convergence markets. Analog Devices said that several DVD equipment manufacturers would soon be announcing new models that incorporate the AD1853.

The AD1853 is the only DAC on the market that meets the new 192-kHz DVD-A sample rate standard. DVD OEMs have been required to consider 96-kHz sample rate DACs; add special digital filters for an expensive, multi-chip solution; or simply to wait for a monolithic IC like the new Analog Devices' DAC. The AD1853 is fully-compatible with all known DVD formats and sample rates. In addition, it is backwards compatible by supporting the 50/15 ýs digital re-emphasis intended for compact discs, as well as 32 kHz and 48 kHz Fs (sampling frequencies).

The unique technology included within the AD1853 (which enables it to attain the new sample rate specification) includes a multibit sigma-delta modulator with "perfect differential linearity restoration" for reduced idle tones and noise floor; patented Data Directed Scrambling techniques for reduced susceptibility to distortion and jitter; as well as continuous time analog filters and special analog output drive circuitry.

The AD1853 is a complete high-performance, single-chip stereo digital audio playback system. Key design features that combine to provide new levels of overall audio performance include: superior signal-to-noise ratio of 117 dB (A-weighted stereo) and 120 dB (A-weighted mono), not muted, at 48 kHz; excellent total harmonic distortion of -104 dB/-107 dB THD + N (stereo/mono); 115-dB stopband attenuation; and programmability through an SPI-compatible serial control port. The new DAC will measurably improve the audio performance of virtually all high-end home and professional audio equipment.

For professional audio systems, the AD1853 offers the best price/performance available. It features a differential, current output for maximum performance and design flexibility. A number of industry leaders have already designed the AD1853 into their systems. For example, Audio Precision of Beaverton, OR, the industry standard for audio measurement, has designed the AD1853 into their latest audio analyzer, the System Two Cascade. And,

Dolby is using the AD1853 in their latest Dolby Digital mastering unit for encoded DVD movies and audio recordings.

As the first 192-kHz part in the market the AD1853 will enjoy considerable success. It is not priced at a premium so that the product will be designed into all of the higher-end products immediately and the remainder of the consumer range quite quickly. Although it has to be assumed that the other significant players are in the design stage this is the kind of market that goes heavily to the early bird solution. The number of vendors with the technology to achieve a high-performance 24-bit stereo part with a 192-kHz sampling is really few in number.

The serial data interface to the part will accept 16, 18, 20 or 24-bit data feeding two (stereo) paths. Each path has an on-chip, clickless, volume control, an 8xFs interpolator and the multi-bit sigma-delta modulator. The output of each path is differential. The 50 mA operating current for the analog circuitry is cut to 60 uA in power down while the digital current is 25 mA, all from a single 5-V supply. Passband ripple is specified at +/-0.001 dB while stopband attenuation is at 115 dB.