900mV programmable gain amplifier for cochlear implants

Power consumption and device area are two critical specifications in implantable cochlear systems. CMOS process scaling has afforded significant area reduction but has increased the difficulty in designing analog circuits due to reduced voltage head room and lower output impedances. In this paper, a programmable gain amplifier (PGA), which is suitable for a full cochlear implant is presented. The core of the PGA is a low-power, low-voltage, switched operational amplifier. The PGA, fabricated in TSMC´s 0.18μm CMOS process, operates from a 900mV supply with a measured power consumption of less then 45μW. These results align favorably with fully implantable systems.