Balanced Voltage-controlled Oscillator Research Articles

A balanced dual-resonance colpitts VCO in 0.18 μm CMOS

A dual-resonance balanced voltage-controlled oscillator (VCO) is proposed to serves as a dual-band oscillator operated at 3.5 and 8.5 GHz. The VCO consists of two single-ended dual-resonance LC-tank complementary Colpitts oscillators configured in a balanced topology. The proposed VCO has been implemented with the TSMC 0.18 μm 1P6M CMOS technology and the core power consumption is 4.21 mW at the supply voltage of 1.2 V. The figure of merit is −190.22/−190.3 dBc/Hz at high/low band. The die area of the dual-band VCO is 0.995 × 0.55 mm2. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:194–197, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27234

A low voltage balanced Clapp VCO in 0.13 micromolar CMOS technology

A balanced voltage-controlled oscillator (VCO) is designed and implemented in a 0.13 μm CMOS 1P8M process.The designed VCO circuit topology is an all nMOS LC-tank Clapp VCO using a series-tuned resonator. At the supply voltage of 0.5 V, the output phase noise of the VCO is −108.69 dBc/Hz at 1 MHz offset frequency from the carrier frequency of 17.72 GHz, and the figure of merit is −186.84 dBc/Hz. The core power consumption is 4.2 mW. Tuning range is about 3.32 GHz, from 17.55 to 20.87 GHz, while the control voltage was tuned from 0 to 1.3 V. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1623–1625, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25275

A 5.6 GHz Low Power Balanced VCO in 0.18 $\mu$m CMOS

A 5.6 GHz balanced voltage-controlled oscillator (VCO) is designed and implemented in a 0.18 mum CMOS 1P6M process. It consists of two single-ended complementary Colpitts LC-tank VCOs coupled by two pairs of varactors. At the supply voltage of 1.2 V, the output phase noise of the VCO is -119.13 dBc/Hz at 1MHz offset frequency from the carrier frequency of 5.6 GHz, and the figure of merit is -190.29 dBc/Hz. Total VCO core power consumption is 2.4 mW. Tuning range is about 600 MHz, from 5.36 to 5.96 GHz, while the control voltage was tuned from 0 to 1.2 V.

A 25-GHz ultra-low phase noise InGaP/GaAs HBT VCO

A 25-GHz monolithic voltage controlled oscillator (VCO) has been designed and fabricated in a commercial InGaP/GaAs heterojunction bipolar transistor (HBT) process. This balanced VCO has a novel topology using a feedback /spl pi/-network and a common-emitter transistor configuration. Ultra-low phase noise is achieved: -106 dBc/Hz and -130 dBc/Hz at 100kHz and 1-MHz offset frequency, respectively. To the authors' knowledge, this is the lowest phase noise achieved in a monolithic microwave integrated circuit (MMIC) VCO at such high frequency. The single-ended output power is -1 dBm. It can be tuned between 25.33GHz and 25.75GHz using the base-collector junction capacitor of the HBT as a varactor. The dc power consumption is 90mW for a 9-V supply. An excellent figure-of-merit of -195 dBc/Hz is obtained.

Noise property of a quadrature balanced VCO

A quadrature balanced voltage controlled oscillator (B-VCO) with current source switching is proposed and analyzed. This letter shows analytically that the switching improves the phase noise. A switched transistor is also used as a coupling transistor to generate quadrature signals without degrading the phase noise. To investigate the effect of quadrature coupling on the phase noise, a single B-VCO and a quadrature B-VCO are implemented with identical components in an 0.18-/spl mu/m CMOS process. Both VCO cores draw about 8.8mA under a low bias voltage of 1.8V. The oscillation frequencies are 10.21GHz and 10.81GHz. The measured phase noises of the single at an offset frequency of 1MHz VCO is -114.83 dBc/Hz while that of the quadrature VCO is -116.67 dBc/Hz. The quadrature B-VCO is superior to the single B-VCO with respect to phase noise and oscillation frequency in the X-band.

Balanced Colpitt oscillator MMICs designed for ultra-low phase noise

Balanced voltage-controlled oscillator (VCO) monolithic microwave integrated circuits (MMICs) based on a coupled Colpitt topology with a fully integrated tank are presented utilizing SiGe heterojunction bipolar transistor (HBT) and InGaP/GaAs HBT technologies. Minimum phase noise is obtained for all designs by optimization of the tank circuit including the varactor, maximizing the tank amplitude, and designing the VCO for Class C operation. Fundamental and second harmonic VCOs are evaluated. A minimum phase noise of less than -112 dBc at an output power of 5.5 dBm is achieved at 100-kHz carrier offset and 6.4-GHz oscillation frequency for the fundamental InGaP/GaAs HBT VCO. The second harmonic VCO achieves a minimum measured phase noise of -120 dBc at 100 kHz at 13 GHz. To our best knowledge, this is the lowest reported phase noise to date for a varactor-based VCO with a fully integrated tank. The fundamental frequency SiGe HBT oscillator achieves a phase noise of -108 dBc at 100 kHz at 5 GHz. All MMICs are fabricated in commercial foundry MMIC processes.