Tuan Vu, Cao3; Wisland, Dag T.4; Lande, Tor Sverre4; Moradi, Farshad5
1 Department of Engineering - Integrated Electronics, Department of Engineering, Science and Technology, Aarhus University2 Aarhus University School of Engineering - Electronics, Aarhus University School of Engineering, Science and Technology, Aarhus University3 University of Oslo4 unknown5 Department of Engineering - Integrated Electronics, Department of Engineering, Science and Technology, Aarhus University
A low-voltage, low-power, and wide-tuning-range VCO which converts an analog input voltage to phase information for a frequency ΔΣ modulator is proposed in this paper. The VCO is based on a differential ring oscillator, which is improved with modified symmetric load and a positive feedback in the differential delay cells, a new bias circuit and a full-swing amplifier. The proposed VCO operating with two stages at a power supply voltage of 0.6 V can achieve wide tuning-range and low power consumption of 176.892 uW. The new VCO has a good linearity reducing harmonic distortion for frequency ΔΣ modulator. The circuit is designed using a 65 nm CMOS process.