Starved picowatt oscillator for remote sensor wake-up timer

A sub-nanowatt oscillator is described. The oscillator is intended for a wake-up timer for remote sensors and hence trades frequency accuracy for reduced power consumption. It is constructed from a five-stage ring of inverters in which the switching speed is reduced using transistors that are always-off, or starved. Fabricated in a 0.35 μm process, the oscillator and its active load dissipate 80 pW at 1.5 Hz from a 1 V supply at 22°C.