Ultra-low-power, ultra-low-voltage 2.12 GHz colpitts oscillator using inductive gate degeneration

An oscillator design technique for low-power and low-voltage applications is presented. The circuit is based on the classical common-gate Colpitts oscillator with additional positive feedback provided by an inductive gate degeneration. This technique decreases the required transconductance to startup oscillations, which makes possible to reduce the minimum supply voltage, and hence the power consumption. A prototype was designed in a standard 0.13 μm CMOS process using a zero-threshold transistor. The post-layout simulation results show an oscillation frequency of 2.12 GHz, with a power consumption of 4 μW under a 40-mV supply voltage.