ABSTRACT
Monolithic inductors and transformers are widely used to improve the performance of most RF ICs thanks to their low cost and ease of integration. They have wide application in power and noise matching for low-noise amplifier (LNA), resonant loads, degeneration, and linearity of amplifiers and mixers. Magnetic components basically provide finite AC impedance with low DC losses and, thanks to this property, they allow circuits to be biased at the supply voltage optimizing the voltage swing and/or maximizing the linearity of the component. Inductors and transformers are also largely used as resonant loads and matching networks in RF power amplifiers, whose efficiency is affected by passive losses. Magnetically coupled monolithic components have a fundamental role in the design of low-noise voltage-controlled oscillator (VCO). Integrated tanks are mandatory at gigahertz frequencies because external components are usually limited by spurious resonances due to parasitic capacitances and bonding wire inductances. The performance in terms of phase noise and oscillation amplitude with respect to current consumption depends on the Q of the LC resonator. Finally, RF filters also are built using monolithic components especially at high operating frequency.
