A 3.3 V current-controlled √-domain oscillator

In this paper, the strong inversion MOS analog of the recently proposed class of log-domain filters, or translinear filters, is proposed. The dynamic root-domain principle, or dynamic voltage-translinear principle, exploits the quadratic law, describing the MOS transistor in the strong inversion region, both to perform an expanding V-I conversion of the capacitor voltages and to implement multiplications and square roots of currents based on the voltage-translinear principle. The presented theory is applied to the design of a current-controlled two-integrator oscillator. Experiment results of a pure CMOS test IC show the feasibility of the root-domain principle. The realized oscillator has a THD of -42 dB and is linearly frequency tunable across 1.3 decades.