Compact wide-range sinusoidal signal generator for in vivo Impedance Spectroscopy

This work presents a compact wide-range fully integrated sinusoidal signal generator for in vivo Electrochemical Impedance Spectroscopy applications. The circuit is based on a novel architecture combining aspects of direct digital synthesis and interpolation digital to analog conversion. The signal generator demonstrates very precise frequency tuning and high spectral purity, while offering a simple architecture and an uncomplicated clocking scheme. The circuit is fabricated using a 0.5μm sea of transistors CMOS process and occupies 0.32mm2 of active die area. Consuming 110μA at a 3V supply, the circuit covers eight decades of frequency from 1mHz to 100kHz and meets the necessary low energy and high precision requirements for implantable bio-diagnostics.