Low power integrated electronics system for the operation of a miniaturized hydration sensor

The application of MEMS devices with integrated electronics are paving the way for a new generation of miniaturized biomedical sensors with the potential of monitoring physiological parameters in the body. This article presents an application-specific integrated circuit (ASIC) that has been designed for integration in a biomedical sensor capable of detecting events associated with the dehydration and overhydration in the body and presents measurement results from a sensor prototype. The sensor converts the hydration level into an osmotic pressure which in turn is translated into a frequency modulated asynchronous digital signal with a 5.71 bit resolution (ENOB). The ASIC was designed and fabricated using the TSMC90nm CMOS processing technology and is based on a low power architecture with a simulated power consumption of 39.4 μW. The circuit layout has a footprint of 565×265 μm² and the linear temperature dependent node of the voltage bandgap reference is used to monitor the temperature.