A 6μW/MHz charge buffer with 7fF input capacitance in 65nm CMOS for non-contact electropotential sensing

Abstract

Capacitive non-contact electric field sensing is a prime modality for signal detection and communication in a variety of contexts ranging from bio-potential measurements and proximity sensing to body centered communication and human computer interaction. Although recent developments in the space of wearable sensors have greatly expanded the sensory capability, they simultaneously place more stringent requirements on the front-end. Thus, low-noise power efficient front-ends that can demonstrate low input parasitic capacitances can accelerate the adoption of sensing and communication technologies that exploit this form of capacitive coupling. To this end, we present results from a 193μm2, 6μW/MHz, unity-gain, charge buffer, fabricated in 65nm CMOS for use in electric field sensing.