Mismatch and temperature compensation for subthreshold seismic sensor system

Abstract

Unattended ground sensors (UGS) are widely used for persistent, surveillance that detects potential threats from intruders without generating false alarms. Battery life is the limiting factor for solutions using digital processing. A 40nW subthreshold analog CMOS (complementary metal oxide semiconductor) chip is fabricated and tested, that wakes up a threat classifying stage. Subthreshold circuits are prone to mismatches and temperature variations, and methods to reduce them are also proposed promising a sturdy UGS. The chip is compared with a previous generation all digital system, consuming 160,000 times less power.