AKM Semiconductor introduced the AK5394, an ultra-high performance 24-bit two-channel A/D converter with 123dB dynamic range, the highest performance available in the industry.

AKM, already positioned as the industryıs performance leader with widely acclaimed 24-bit A/D converters, now allows for audio systems to sample up to 192kHz, another industry first for AKM. With specifications matched for the demands of DVD-audio offering improved sampling performance, the AK5394 features a built-in high performance digital filter and the widest dynamic range in the industry today. These advances make it ideal for consumer products such as AV amplifiers, and for high-end Professional audio equipment such as DVD editing system and digital mixers.

The new AK5394 is near pin-compatible with the previous converters from AKM, the AK5393 a 24-bit stereo A/D Converter with 96kHz sampling and 117dB performance. Released in June 1998 and well regarded for its performance standard in many high-end consumer and professional applications. This new converter allows for a wider sampling range and improved performance.

This new release uses AKMıs newly developed delta-sigma modulator to achieve the market-first 123dB audio ADC performance. The advanced multi-bit delta-sigma technology has enabled achievement of a dynamic range that is twice that of previous enhanced dual-bit systems. This new modulator offers many other advantages never allowed before, such as the first ADC to achieve 123dB and consume less than 600mW, beatting the nearest competition by 3dB and by cutting their power by two-thirds.

AKM has continually been at the top level of performance in the audio/digital conversion world and the company's products deserve to be more looked at by designers on this side of the Pacific than they often are. This is a top-of-the-range ADC for stereo audio, matching the 192 kHz DACs that are already reaching the market. The specifications are outstanding and must be very close to the limits of measurement. The interchannel isolation lives fully up to the numbers as well at 120 dB and the channel matching is within 0.1 dB.

The term "near pin-compatible" with the previous AK5393 would probably send shivers down the spines of most design engineers -- especially when a manager tells you to "drop in" this new part -- but in fact the changes are four minor ones and, most importantly, do not involve any ground re-routing. The part needs a 5-V analog supply and a 3.3- to 5-V digital supply. The typical analog quiescent is 127 mA while the digital drain varies from 9 to 21 mA as the sampling moves from 48 kHz to 192 kHz. Unlike the AK5393 the new part includes a digital high-pass filter for dc offset cancellation with a cut-off frequency of 1 Hz.

Like the previous parts the AK5394 has fully differential inputs and is highly suitable for the most professional audio acquisition system. AKM does need to "Americanize" the data sheets a little more; apart from English like "the phase is free of care," recommended input circuits using a New Japan Radio (JRC) op amp -- the NJM5534 -- will probably be outside most U.S. designers' experience. [The NJM5534 is actually a low noise (3.3 nV/rtHz) 200 kHz op amp in DIP-8 or DMP-8 that can be easily replaced with whatever is your favorite (mine would be the OPA227).]