Study Of Class C Voltage Control Oscilator In 65nm CMOS IC

Oscillator is a device which does not need additional stimulated signal to transfer DC power to periodicity AC power. It is one of the most important component in lots of electronic systems, widely applied. With wireless communication industry developing, especially popularization of handheld wireless devices like mobile phone, RF front-end chip is designed tend to smaller, cheaper, and lower power consumption. Assuming a transceiver could realize half voltage or lower supply power, then solar energy could be the source of the supply power, which would contribute a lot to energy conservation and emission reduction.Among communication circuits, VCO always plays a critical role, especially in Phase Lock Loop, Clock-recovery Circuits and Frequency Synthesizer. It is no exaggeration to say VCO is as important as Current Source and Power Amplifier in electronic communication.This paper proposed a Class-C voltage-control-oscillator(VCO) IC with an amplitude feedback loop for ultra-low-voltage like solar power application. The main contents are as follows.1. Study the origins of Class-C VCO, explain why it can decrease phase noise and consumption more effectively than other kinds of VCO. Find the key points of its structure and the rules.2. Study the existed problems of the cross coupled LC-VCO at present. For instance, simplify the structure of circuit, how to decrease the consumption from the resonance circuit, and so on.3. Design a dynamical bias circuit, which is an amplitude feedback loop to shift LC-VCO bias condition from initial Class-AB start-up to steady Class-C low current oscillation.4. Design two stage buffer amplifier, first stage is for high input impedance, second one is for widen the tuning rage of the VCO to get oscillation easily.5. This research is based on Cadence development environment and Goldengate simulation tools, adopted 65-nm RF CMOS process. Realized a low power consumption Class-C LC VCO, whose central frequency is 2.43 GHz.In the end, the fabricated Class-C VCO IC exhibits a measured phase noise of-111 d Bc/Hz at 1 MHz offset from the 2.43 GHz carrier frequency at a supply voltage of only 0.3 V.