Super Audio CD: The Rich Report References, Multibit Converters
Less activity is occurring in state-of-the-art audio converters because the market is much smaller for these. Analog Devices and Philips are sitting things out, while Burr-Brown appears to be concentrating on lower-cost chips for use in CD-R, MiniDisc, and A/V receivers. Most companies are busy working on converters for DSL rather than audio. DSL has some very tough requirements, and many of these are multibit delta-sigma structures. We will not reference these here.
I. Fujimori, et al, "A 5V Single-Chip Delta-Sigma Audio A/D Converter with 111dB Dynamic Range," IEEE Journal of Solid-State Circuits, Vol.32 No.3 (March 1997), p.329. This paper is the flip side of a MASH DAC chip. The AKM ADC paper above is a new MASH architecture. This MASH architecture gives rise to two bits each DSM clock cycle. AKM does some interesting stuff to eliminate idle tones and to maximize dynamic range.
Y. Ka, et al, "5V, 118dB Delta-Sigma Analog-to-Digital Converter for Wideband Digital Audio," ISSCC Digest of Technical Papers, February 1997, pp.218-219. This paper describes an important three-level design by Crystal Semiconductor.—David Rich