Subthreshold CMOS active inductors with applications to low-power injection-locked oscillators for passive wireless microsystems

This paper investigates gyrator-C active inductors in weak inversion. An injection-locked active inductor oscillator in weak inversion designed in IBM-0.13µm 1.2V CMOS technology and analyzed using SpectreRF from Cadence Design Systems with BSIM4 device models. The injection-locking signal is generated using a generic ring oscillator. Simulation results show that the phase noise of the injection-locked active inductor VCO is much smaller as compared with that of the same active inductor VCO but without injection-locking. Also observed is that the phase noise of the injection-locked active inductor VCO is approximately the same as that of injection ring VCO when frequency offset is less than 200 kHz and increases when frequency offset is beyond 200 kHz. The power consumption of the oscillator is 776 nW at 13 MHz. With the proper biasing voltage, the tuning range of active inductor VCO is from 6.5 MHz to 34.6 MHz. The layout area of the injection-locked oscillator including bond pads and an output buffer is 0.67 mm2. The silicon consumption of the core of the oscillator is only 13 µm2.