A High-Performance Third-Order Sinusoidal Oscillators Using a Single VDBA with Frequency Tunability

This paper presents a generic topology for realizing high performance third order sinusoidal oscillators (SOs) using a single voltage differencing buffered amplifier (VDBA). The proposed structure can be configured into four oscillator variants by selecting three resistors and three capacitors appropriately. The frequency of oscillation (FO) can be independently tuned with respect to capacitive components without affecting the condition of oscillation (CO) for all four configurations. The topology also provides low-impedance voltage outputs, enabling easy cascading in larger analog signal processing systems. Moreover, the proposed oscillator topologies exhibit low sensitivity of FO to circuit parameter variations across the operating range, and a detailed non-ideality analysis is included to analyze the impact of device imperfections on circuit performance. The oscillators are implemented and validated using the 180 nm GPDK CMOS technology in Cadence Virtuoso. It operates at the supply voltage of ± 0.9 V and provides transconductance (g m ) of 1.398 mS for the pre-layout simulation and 1.41 mS for the post-layout simulation. The proposed oscillator exhibits a wide tuning range from 30 kHz to 12 MHz, low total harmonic distortion below 3%, and low power consumption. Frequency stability and phase-noise analyses are also presented to evaluate the spectral performance of the proposed topologies. Simulation results including Monte Carlo, process-corner, supply-voltage, and temperature analyses, together with experimental verification, confirm the robustness and practical applicability of the proposed design. To demonstrate practical applicability, a DSB-SC amplitude modulator is also designed using the proposed oscillator.