A 700-μW single-chip IC for wireless continuous-time health monitoring in 0.18-μm CMOS

A sensor node was designed and implemented in 0.18 μm CMOS process. The sensor node consists of a sensor interface circuit, an analog-to-digital converter (ADC), a digital signal processor (DSP) unit and a radio-frequency (RF) transmitter unit. The sensor node was designed for use in a wireless health monitoring system. Minimal off-chip components are allowed in this implementation for improved user experience, which are antenna, crystal resonator and supply decoupling capacitors. Low-power low-voltage design techniques such as sub-threshold design were employed intensively to minimize the power consumption of the sensor node IC and maximize the battery life. The sensor consumes only about 700 μW at 0.7 V supply and it enables continuous-and real-time electrocardiogram (ECG) monitoring for more than 200 hours without changing the battery when a typical button-cell battery is used.