A Low-Voltage Quadrature CMOS VCO Based on Voltage-Voltage Feedback Topology

A novel low-voltage quadrature voltage-controlled oscillator (QVCO) with voltage feedback to the input gate of a switching amplifier is proposed and implemented using the standard TSMC 0.18-mum CMOS 1P6M process. The proposed circuit topology is made up of two low-voltage LC-tank VCOs, where the coupled QVCO is obtained using the transformer coupling technique. At the 0.7-V supply voltage, the output phase noise of the VCO is -124.9 dBc/Hz at 1-MHz offset frequency from the carrier frequency of 2.4GHz, and the figure of merit is -185.35dBc/Hz. Total power consumption is 5.18 mW. Tuning range is about 135 MHz while the control voltage was tuned from 0 to 0.7V     

8-GHz CMOS quadrature VCO using transformer-based LC tank

A fully integrated quadrature VCO at 8 GHz is presented. The VCO is implemented using a transformer-based LC tank in 0.18 /spl mu/m CMOS technology, in which two VCOs are coupled to generate I-Q signals. The VCO is realized employing the drain-gate transformer feedback configuration proposed here. This makes use of the quality factor enhancement in the resonator using a transformer and the deep switching-off technique by controlling gate bias. By turning off switching transistors of the differential VCO core deeply, the phase noise performance is improved more than 10 dB. The measured phase noise values are -110 and -117 dBc/HZ at the offset frequencies of 600 kHz and 1 MHz respectively. The tuning range of 250 MHz is achieved with the control voltage from 0 to 1 V. The VCO draws 8 mA in two differential core circuits from 3 V supply. When the bias voltage goes down to 2.5 V, the phase noise decrease only 2 dB compared to that of 3 V bias. The VCO performances are compared with previously reported quadrature Si VCOs in 5/spl sim/12 GHz frequency range.     

5-GHz Low Power Current-Reused Balanced CMOS Differential Armstrong VCOs

This letter proposes 5-GHz low power differential Armstrong voltage controlled oscillators (VCOs) based on balanced topology. One designed VCO uses two single-ended Armstrong VCOs coupled to each other in parallel by balanced structure. The other current-reused VCO uses two single-ended Armstrong VCOs stacked in series. The former VCO oscillates from 4.96 to 5.34GHz and the power consumption is 3.9mW at 0.6-V supply voltage. The latter operates from 4.98 to 5.45GHz and dissipates 2.59mW at 1.8-V supply voltage. The measured phase noises are about -116.71dBc/Hz and -110.02dBc/Hz at 1-MHz offset frequency from 5.1-GHz band, respectively. The former and the latter VCO have an advantage of low power consumption and provide a good figure of merit of about -185dBc/Hz and -180dBc/Hz, respectively     

A Low-Power 114-GHz Push–Push CMOS VCO Using LC Source Degeneration

An LC source-degeneration negative-resistance cell of an LC VCO is investigated, which is capable of operating at millimeter-wave (MMW) range with low dc power consumption. Several negative-resistance cells in LC oscillators are also compared. The LC source-degenerated topology is demonstrated through a 114-GHz push-push fully integrated LC VCO implemented in TSMC 0.13-mum CMOS process. With core power consumption of 8.4 mW, the tuning range at the fundamental port is 56.4-57.6 GHz and at the push-push port is 112.8-115.2 GHz. The measured phase noise at the fundamental port is -13.6 dBc/Hz at 10-MHz offset. This VCO is believed to have the best figure of merit among MMW VCOs using bulk CMOS processes.     

A low-phase-noise K-band CMOS VCO

A novel circuit topology for low-phase-noise voltage controlled oscillators (VCOs) is presented in this letter. By employing a PMOS cross-coupled pair with a capacitive feedback, superior circuit performance can be achieved especially at higher frequencies. Based on the proposed architecture, a prototype VCO implemented in a 0.18-/spl mu/m CMOS process is demonstrated for K-band applications. From the measurement results, the VCO exhibits a 510-MHz frequency tuning range at 20GHz. The output power and the phase noise at 1-MHz offset are -3dBm and -111dBc/Hz, respectively. The fabricated circuit consumes a dc power of 32mW from a 1.8-V supply voltage.     

11-GHz CMOS differential VCO with back-gate transformer feedback

A fully integrated back-gate transformer feedback CMOS differential voltage-controlled oscillator (VCO) has been designed for high-frequency and low-phase noise operation using an 0.18-/spl mu/m CMOS process. The proposed VCO topology utilizes the monolithic transformer feedback configuration from the drain to the back-gate of the switching transistors in VCO. The VCO operating in an 11-GHz band shows the phase noise of -109dBc/Hz at 1-MHz offset, and draws around 3.8mA in the differential core circuits from a 1.8-V power supply.     

A Millimeter-Wave CMOS LC-Tank VCO With an Admittance-Transforming Technique

A novel circuit topology suitable for millimeter-wave voltage-controlled oscillators (VCOs) is presented. With the admittance-transforming technique, the proposed VCO can operate at a frequency close to the f_max of the transistors while maintaining remarkable circuit performance in terms of phase noise, tuning range, and output power. Using a standard micrometer CMOS process, a U-band VCO is implemented for demonstration. The fabricated circuit exhibits a frequency tuning range of 1.1 GHz in the vicinity of 50 GHz. The measured output power and phase noise at 1-MHz offset are -11 dBm and -101 dBc/Hz, respectively. Operated at a supply voltage of 1.8 V, the VCO core consumes a DC power of 45 mW.     

A High-Performance CMOS Voltage-Controlled Oscillator for Ultra-Low-Voltage Operations

In this paper, a novel circuit topology of voltage-controlled oscillators (VCOs) suitable for ultra-low-voltage operations is presented. By utilizing the capacitive feedback and the forward-body-bias (FBB) technique, the proposed VCO can operate at reduced supply voltage and power consumption while maintaining remarkable circuit performance in terms of phase noise, tuning range, and output swing. Using a standard 0.18-mum CMOS process, a 5.6-GHz VCO is designed and fabricated for demonstration. Consuming a dc power of 3 mW from a 0.6-V supply voltage, the VCO exhibits a frequency tuning range of 8.1% and a phase noise of -118 dBc/Hz at 1-MHz offset frequency. With an FBB for the cross-coupled transistors, the fabricated circuit can operate at a supply voltage as low as 0.4 V. The measured tuning range and phase noise are 6.4% and -114 dBc/Hz, respectively     

一种双带宽UHF主从耦合式LC VCO

为了满足无线通信系统应用需要,设计了一种主从耦合式LC压控振荡器(VCO).基于0.18 μm CMOS标准工艺,由一个5 GHz主VCO和两个起分频作用的从VCO组成,其中主VCO选用PMOS考毕兹差分振荡结构,在两个互补交叉耦合的从VCO的输出端之间设置有注入式NMOS器件以达到分频的目的.仿真及硬件电路实验结果表明,在1.8 V低电源电压下,5 GHz主VCO的调谐范围为4.68～5.76 GHz,2.5 GHz从VCO的调谐范围为2.32～2.84 GHz;在1 MHz的偏频下,5 GHz主VCO的相位噪声为118.2 dBc/Hz,2.5 GHz从VCO的相位噪声为124.4 dBc/Hz.另外,主从VCO的功耗分别为6.8 mW和7.9 mW,因此特别适用于低功耗、超高频短距离无线通信系统中.     

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.     

Low noise 5 GHz differential VCO using InGaP/GaAs HBT technology

The authors present the first InGaP/GaAs HBT differential VCOs with low phase noise performance. One is a cross coupled differential VCO, and the other is a Colpitts differential VCO. To achieve a fully integrated VCO, collector-base junction capacitance of HBT transistor is used for the frequency tuning varactor. The measured output frequency ranges of VCOs are 290 MHz and 190 MHz, and the phase noises at an offset frequency of 1 MHz are -118 dBc/Hz and -117 dBc/Hz respectively. The each VCO core dissipates 13.2 mW from a 3.5 V supply, and the output power is about -0.2 dBm. Concerned with cross coupled VCO, it shows the figure of merit of -179 dBc/Hz, which is the best result among the reported compound semiconductor FET and HBT VCOs.     

LC-Tank Colpitts Injection-Locked Frequency Divider With Record Locking Range

A new wide locking range injection-locked frequency divider (ILFD) using a standard 0.18-$mu$ m CMOS process is presented. The ILFD is based on a differential voltage controlled oscillator (VCO) with two embedded injection metal oxide semiconductor field effect transistors (MOSFETs) for coupling external signal to the resonators. The new VCO is composed of two single-ended VCOs coupled with cross-coupled MOSFETs and a transformer. Measurement results show that at the supply voltage of 1.5 V, the divider's free-running frequency is tunable from 5.85 to 6.17 GHz, and at the incident power of 0 dBm the locking range is about 7.1 GHz (65.4%), from the incident frequency 7.3 to 14.4 GHz. The ILFD has a record locking range percentage among published divide-by-2 $LC$-tank ILFDs.      

Design of Wide Tuning-Range CMOS VCOs Using Switched Coupled-Inductors

Two designs of voltage-controlled oscillators (VCOs) with mutually coupled and switched inductors are presented in this paper to demonstrate that the tuning range of an LC VCO can be improved with only a small increase in phase noise and die area in a standard digital CMOS process. Particular attention is given to the layout of the inductors to maintain Q across the tuning range. In addition, different capacitive coarse-tuning methods are compared based on simulated and measured data obtained from test structures. Implemented in a 90 nm digital CMOS process, a VCO with two extra coupled inductors achieves a 61.9% tuning range with an 11.75 GHz center frequency while dissipating 7.7 mW from a 1.2 V supply. This VCO has a measured phase noise of -106 dBc/Hz at 1 MHz offset from the center frequency resulting in a higher figure-of-merit than other recently published VCOs with similar operating frequencies. In addition, the area overhead is only 30% compared to a conventional LC VCO with a single inductor.     

On the use of MOS varactors in RF VCOs

This paper presents two 1.8 GHz CMOS voltage-controlled oscillators (VCOs), tuned by an inversion-mode MOS varactor and an accumulation-mode MOS varactor, respectively. Both VCOs show a lower power consumption and a lower phase noise than a reference VCO tuned by a more commonly used diode varactor. The best overall performance is displayed by the accumulation-mode MOS varactor VCO. The VCOs were implemented in a standard 0.6 μm CMOS process     

LC-Tank Colpitts Injection-Locked Frequency Divider With Even and Odd Modulo

A new injection-locked frequency divider (ILFD) using a standard 0.18 $mu$m CMOS process is presented. The ILFD is based on a differential Colpitts voltage controlled oscillator (VCO) with a direct injection MOSFET for coupling an external signal to the resonators. The VCO is composed of two single-ended VCOs coupled with two transformers. Measurement results show that at the supply voltage of 1.4 V the divider's free-running frequency is tunable from 4.77 to 5.08 GHz, and the proposed circuit can function as a first harmonic injection-locked oscillator, divide-by-2, -3, and -4 frequency divider. At the incident power of 0 dBm the divide-by-2 operation range is from the incident frequency 7.7 to 11.5 GHz and the divide-by-4 operation range is from the incident frequency 18.9 to 20.2 GHz.      

Ring-Based Triple-Push VCOs With Wide Continuous Tuning Ranges

This paper proposes a new ring-based triple-push voltage-controlled oscillator (VCO) architecture to achieve a wide tuning range and high operating frequencies. Two ring-based triple-push VCOs, one with a continuous frequency tuning range of 0.2-34 GHz, fabricated in 0.13- mum CMOS, and the other with a range of 0.1-65.8 GHz, fabricated in 90-nm CMOS, are presented in this paper. These two VCOs demonstrate that the proposed VCO architecture can achieve a very wide continuous tuning range, up to millimeter-wave frequencies, without any device-switching operations. In addition to the wide tuning range, the chip area of the proposed VCO is very small, allowing integration into a phase-locked loop. The power consumptions of the 0.2-34- and 0.1-65.8-GHz VCOs are 2-70 mW from a 2-V supply voltage, and 1.2-26.4 mW from a 1.2-V supply voltage, respectively. The fundamental and second harmonic rejections are better than 15 dB for both VCOs.     

A low-power low-phase-noise LC VCO with MEMS Cu inductors

A 2-3 GHz CMOS inductance-capacitance (LC) voltage-controlled oscillator (VCO) integrated with high-Q micro-electromechanical systems (MEMS) Cu inductors is reported. While dissipating only 6.3 mW, a phase noise of -121 dBc/Hz at 600 kHz offset from 2.78 GHz carrier is achieved. This MEMS VCO has the largest power-frequency normalized figure-of-merit (12.5 dB) among the Si bipolar and CMOS LC VCOs.     

A -119.2 dBc/Hz at 1 MHz, 1.5 mW, fully integrated, 2.5-GHz, CMOS VCO using helical inductors

This letter presents an implementation to reduce area occupation in designing voltage-controlled oscillators (VCOs) using a filtering technique. We applied a helical inductor to the noise filter in a 2.5-GHz CMOS VCO to reduce area occupation. Because a helical inductor has less area occupation, a small silicon area was achieved. This VCO operates in the 2.5-GHz band with power consumption of 1.5 mW and phase noise of -119.2 dBc/Hz at 1-MHz. Our VCO displays an excellent performance of phase noise in relation to power consumption.     

A Fundamental 90-GHz CMOS VCO Using New Ring-Coupled Quad

A new circuit topology, named ring-coupled quad for millimeter-wave voltage controlled oscillator (VCO) design, is proposed. The proposed circuit topology provides higher open loop voltage gain than conventional cross-coupled pair. The layout of the proposed ring-coupled quad is fully symmetric without additional interconnection lines. A 90-GHz VCO using 90-nm CMOS process is implemented with this ring-coupled quad. This 90-GHz oscillator demonstrates a 2.5-GHz tuning range and higher than -20dBm output power. The proposed ring-coupled quad is suitable for the realization of high frequency VCOs     

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.