Battery supplied low power analog-digital front-end for audio applications

This paper presents the development of a full custom low power, mixed-mode, analog digital front-end chip for audio applications. The front-end is used with a full custom DSP ASIC in a high performance hearing aid system. The front-end implements functions as preamps, low power stereo audio analog to digital converters, remote-control receiver, high PSSR power supplies, time base, voltage reference and a DC-DC converter. The chip has around 170K MOS and is operating down to 0.9V from the battery. The chip is produced using a 0.35 µm, 3.3V CMOS process with quadruple metal, two poly resistors and double poly capacitors.

[1]  G. van Oerle,et al.  A 660-/spl mu/W 50-Mops 1-V DSP for a hearing aid chip set , 2000, IEEE Journal of Solid-State Circuits.

[2]  Lajos Gazsi,et al.  Explicit formulas for lattice wave digital filters , 1985 .

[3]  G. Nicollini,et al.  Low-voltage double-sampled /spl Sigma//spl Delta/ converters , 1997, 1997 IEEE International Solids-State Circuits Conference. Digest of Technical Papers.

[4]  C. Piguet,et al.  On the use of modulo arithmetic comb filters in sigma delta modulators , 1988, ICASSP-88., International Conference on Acoustics, Speech, and Signal Processing.

[5]  C. Piguet,et al.  Low-power design of 8-b embedded CoolRisc microcontroller cores , 1997, IEEE J. Solid State Circuits.

[6]  Robert Henderson,et al.  A 19-bit low-power multibit sigma-delta ADC based on data weighted averaging , 1997 .