A 63–89-kHz 1/<i>f</i>³ Phase Noise Corner QVCO Using Enhanced Wideband-Harmonic-Shaping Technique

A quadrature voltage-controlled oscillator (QVCO) utilizing the enhanced wideband-harmonic-shaping technique to improve phase noise (PN) and reduce the 1/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f} ^{3}$ </tex-math></inline-formula> PN corner is presented. Specifically, our QVCO uses triple-coil magnetic coupling for quadrature phase generation, additionally boosts the common-mode (CM) impedance and harmonic voltage, and contributes to a well-defined CM current returning path for PN improvement and flicker noise upconversion reduction. Besides, the head resonator (HR) enables wideband-harmonic-shaping operation and facilitates without manual second harmonic alignment. The QVCO is implemented in 55-nm CMOS and occupies a core area of 0.362 mm2. The measured peak PN is −124.2 dBc/Hz at 1-MHz offset, and the estimated 1/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f} ^{3}$ </tex-math></inline-formula> PN corner varies from 63 to 89 kHz across the entire operating range of 17% (4.14–4.97 GHz).