Hearing instruments go digital

This paper describes the backgrounds, required performances and choices made at system and circuit level to make a digital hearing aid, competitive in power and area with analog solutions. Power consumption of the digital circuitry working at 1.1 V equals that of the on-board analog interface circuitry. Though chip area is 35 square mm, and digital area takes about 80%, the rapid development of CMOS processes makes this the turning point in going from full analog to digital solutions.