12.6 A 160nW 63.9fJ/conversion-step capacitance-to-digital converter for ultra-low-power wireless sensor nodes

Recent advances in nW-level wireless sensor nodes have created opportunities in emerging applications such as bio-implantable telemetry, smart healthcare, and environmental monitoring [1]. At the same time, there are many circuit and system design challenges to achieving high functionality in such ultra-low-power microsystems. One of the key sensing modalities in these systems is capacitive sensing. With zero static current during signal readout, capacitive sensing is well suited to ultra-low-power microsystems and has been widely adopted in the sensing of pressure [2,3], displacement [4], and humidity [5].