A 196.5 dBc/Hz FOM T 16.8–21.6-GHz Class-F23 CMOS VCO With Transformer-Based Optimal Q-Factor Tank

Abstract

This letter presents an optimal tank- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> Class-F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">23</sub> voltage-controlled oscillator (VCO) in 65-nm CMOS. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> -factor of the transformer-based multi-LC resonator is maximized in the Class-F operation mode by the proposed graphical <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> -optimization method. The frequency tuning range (TR) is expanded by 26% as well. The phase noise (PN) is improved by reshaping the impulse sensitivity function (ISF) with the 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nd</sup> and 3 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup> harmonic tuning. Occupying 0.112 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , the VCO at 16.8 GHz exhibits −112.2 dBc/Hz PN at 1 MHz offset and 196.5 dBc/Hz <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{FOM}_{T}$ </tex-math></inline-formula> at 10 MHz offset. The measured TR is 25% (16.8–21.6 GHz). The oscillator core consumes 7 mW at 1 V supply.