A Low-Power Microinstrument for Chemical Analysis of Remote Environments

The need for small, reliable, and accurate microsystems that can remotely monitor earth and extraterrestrial environments has increased demand for single-chip microinstruments with long lifetimes. This paper presents work toward a monolithic, lowpower, mixed-signal microcontroller that is capable of measuring, processing, and storing data from liquid chemical sensors. The system consists of a potentiostatic interface circuit, programmable gain amplifier, analog-to-digital converter, microprocessor core, on-chip memory, and a CMOS-MEMS monolithic clock reference. The microinstrument was designed in TSMC’s 0.18 μm CMOS process and operates from a nominal 1.8 V supply that is scalable down to 900 mV. The system consumes 50 mW at a nominal operating frequency of 62.5 MHz.