VOLTAGE CONTROLLED OSCILLATOR DECREASING PHASE NOISE WITH STABILITY TO PROCESS VARIATION

摘要

A voltage controlled oscillator for reducing phase noise with stability to a surrounding environment is provided to reduce the phase noise by forming a source resistance in an AC block unit and maintaining a source voltage of a transistor of a negative resistance unit. An LC tank unit(210) receives a supply voltage and oscillates a first and second oscillation terminals for generating frequency control signals according to a control voltage. A negative resistance unit(220) includes first and second transistors. Each of the first and second transistors maintains each oscillating state of the first and second oscillation terminals by using negative resistances. A DC block unit(230) couples the first control terminal with the second oscillation terminal and couples the second control terminal with the first oscillation terminal. An AC block unit(240) includes a source resistance formed between junction terminals of the first and second transistors and the ground. A bias unit(250) is controlled by the junction terminal in order to maintain a voltage of the junction terminal of the first and second transistors stably and to supply first and second feedback voltages to the first and second control terminals.