Design of highly programmable bio-impedance measurement IC in 0.18μm CMOS

In this paper, a highly programmable bio-impedance measurement system for multi-purpose health monitoring application is presented. Complex and area consuming analog components are replaced by a high resolution ADC and digital processing providing lots of flexibility to both designers and users. The prototype of the proposed system architecture is designed in 0.18μm CMOS technology. The tuning range of signal generator is from 10kHz∼10MHz and current variation of voltage-controlled current source (VCCS) is below 1%. The gain, bandwidth, CMRR and input referred noise of instrumentation amplifier (IA) are 18dB, 1.5Hz∼9.5MHz, 96.7dB at 100kHz and 10.3nV/√Hz, respectively. ADC is implemented using pseudo-differential VCO-based architecture. Signal-to-noise ratio (SNR), spurious-free dynamic range (SFDR) and signal-to-noise-and-distortion ratio (SNDR) of ADC are 87.5dB, 60dB and 60dB, respectively. The total power consumption of prototype is 6.7mW.