Improved implementation of the silicon cochlea

The original "analog electronic cochlea" of Lyon and Mead (1988) used a cascade of second-order filter sections in subthreshold analog VLSI to implement a low-power, real-time model of early auditory processing. Experience with many silicon-cochlea chips has allowed the identification of a number of important design issues, namely dynamic range, stability, device mismatch, and compactness. In this paper, the original design is discussed in light of these issues, and circuit and layout techniques are described which significantly improve its performance, robustness, and efficiency. Measurements from test chips verify the improved performance.