Ultra-Low-Power Low-Frequency CMOS Integrated Oscillators for Energy-Efficient IoT Devices

The design of ultra-low-power Hz-range oscillators is investigated utilizing transistor operation near super-cutoff region. Two oscillator topologies are proposed based on ring oscillator and relaxation oscillator architectures. The oscillators realized in CMOS 90 nm technology, are enabled to operate across a wide supply voltage, thereby allowing them to be solely powered from energy harvesting sources without requiring power-intensive voltage regulation. The performance of the oscillators is also verified over a practical temperature range of -20°C to 40°C. The power requirement is restricted within the nanowatt range, thereby making them highly suitable for energy-efficient and compact IoT devices.