A low-voltage translinear second-order quadrature oscillator

This paper describes the design of a low-voltage translinear second-order quadrature oscillator. The circuit is a direct implementation of a nonlinear second-order state-space description and follows from a recently developed synthesis method for dynamic translinear circuits. It comprises only two capacitors and a handful of bipolar transistors and can be instantaneously controlled over a very wide frequency range by only one control current, which indicates its suitability for spread-spectrum communications. Its total harmonic distortion can be made small by the design. Simulations, using realistic transistor models of a 1, 15-GHz, bipolar IC process, indicate that the oscillator operates from a single supply voltage, which can be as low as 1 V and oscillates over 8.4 decades of frequency (from 50 mHz to 13 MHz) with less than 2 % total harmonic distortion. Its quadrature phase error equals 0.31 degrees.