1 ∼ 3GHz VCO with rail-to-rail V_CONT range

Abstract

This paper presents a 1 ∼ 3GHz voltage controlled oscillator (VCO) with a rail-to-rail VCO tuning voltage (V_CONT) range. To obtain wide and linear V_CONT range, a new differential amplifier with a rail-to-rail common mode input range and an unstacked output stage is proposed. By using the proposed differential amplifier in the analog fine tuning block, V_CONT can span almost the rail-to-rail supply voltage with good linearity. For verification, a prototype VCO was fabricated in a 65nm 1P7M CMOS process.