Wide Tuning Range Voltage-controlled Oscillator Research Articles

A 267 GHz Wide Tuning Range VCO With −3.5 dBm Peak Output Power in 40-nm CMOS

This article presents a highly efficient, wide tuning range push-push voltage-controlled oscillator (VCO) in the sub-terahertz frequency band. The proposed VCO adopted a novel capacitance-splitting feedback technique to achieve high oscillation frequency and output power. The frequency tuning is provided through a tunable source degeneration (TSD) network. The proposed TSD network enables a wide tuning range without substantially sacrificing output power. The proposed VCO is fabricated in a 40-nm complementary metal-oxide-semiconductor (CMOS) process and has a peak output power of −3.5 dBm, a center frequency of 267.2 GHz, and a continuous tuning range of 27 GHz. The VCO consumes 30 mA current from a 1.1 V dc supply, resulting in 1.35% dc-to-RF efficiency.

A New Boosted Active-Capacitor With Negative-G m for Wide Tuning Range VCOs

A new boosted active-capacitor (BAC) architecture using LC-tuned active-impedance-conversion is presented. In the chosen frequency range, the proposed BAC acts as a tunable capacitance multiplier and negative-transconductance, but where the positive-transconductance is not multiplied. The BAC is used as a low-loss tunable capacitor bank element for designing a wide tuning range voltage-controlled oscillator (VCO). A current-reuse technique is used to lower power consumption and suppress potential parasitic oscillation modes. A zero-capacitance-variation biasing is proposed for a BAC-VCO robust against process, voltage, and temperature variations. The BAC designed in a 65 nm bulk CMOS process achieves a capacitance tuning ratio of 7.8 with a quality factor of higher than 20 across VCO's tuning range. The BAC-VCO prototype has a tuning range of 8.3-14.3 GHz using less than 5 mW core power and achieves FoMT of up to -202.4 dBc/Hz.

A Wide Tuning Range, Low Phase Noise, and Area Efficient Dual-Band Millimeter-Wave CMOS VCO Based on Switching Cores

This paper presents a millimeter-wave wide tuning range voltage-controlled oscillator (VCO) incorporating two switchable decoupled VCO cores. When the first core is switched on producing the low frequency band (LFB) signal and the second core is off, the inductors of the second core are reused to create additional buffers that pass the LFB signal to the output buffers. The generated high frequency band (HFB) signals by the second core when turned on, are directly fed to the output buffers. Producing the outputs of both VCO cores across same terminals without utilizing active/passive combiners and coupled inductors will enhance the phase noise performance of the VCO, increase its output power, and reduce the chip size. Fabricated in a 65-nm CMOS process, the VCO achieves a measured wide tuning range of 26.2% from 54.1 to 70.4 GHz while consuming 7.4-11.2-mA current from 1-V power supply. The peak measured phase noise at 10-MHz offset is -116.3 dBc/Hz and the corresponding FOMT and FOM varies from -180.96 to -191.86 dB and -172.6 to -183.5 dB, respectively. The VCO core area occupies only 0.1 ×0.395 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

A wide tuning range VCO design using multi-pass loop complementary current control with IMOS varactor for low power applications

In this work a wide-bandwidth low-power voltage-controlled oscillator (VCO) design is presented using a new differential delay cell with complementary current control mechanism and inversion mode MOSFET (IMOS) varactor. The variations in output oscillation frequency of the VCO has been achieved by changing the capacitance of the delay cell with the usage of IMOS varactor containing two PMOS transistors connected in parallel. The proposed three-stage VCO has been designed with 1.8 V power supply in 180 nm CMOS technology. Capacitance of IMOS varactor has been varied by altering the source/drain voltage Vcontrol and back-gate voltage Vsb of IMOS. The variations in power supply voltage from 1 V to 2.4 V provides output frequency from 1.893 GHz to 7.926 GHz with power dissipation of 0.953 mW to 24.261 mW with IMOS varactor width of 5 µm. The results have been extended for the IMOS width of 10 µm, 15 µm and 20 µm. The tuning range of 122% has been achieved with the power supply tuning method. The variations in source/drain voltage of IMOS from 1 V to 2.4 V provides the output frequency from 6.373 GHz to 5.460 GHz with power dissipation of 9.62 mW. The tuning range of 15.7%, 22.3%, 44% and 40.6% has been obtained for IMOS with widths of 5 μm, 10 μm, 15 μm and 20 μm with the source/drain voltage Vcontrol variations. Further, frequency variation from 5.895 GHz to 6.406 GHz has been obtained with back-gate voltage Vsb tuning of IMOS varactor from 0 V to 2.4 V. The phase noise measured for the VCO is −90.67 dBc/Hz@1 MHz and the figure of merit (FoM) for the VCO is 172.86 dBc/Hz with supply voltage of 1.8 V. Proposed VCO circuit achieved a low power dissipation, wide tuning range, better phase noise and figure of merit (FoM).

Switched Substrate-Shield-Based Low-Loss CMOS Inductors for Wide Tuning Range VCOs

A switched substrate-shield inductor (SSI) topology in bulk CMOS is proposed which minimizes parasitic capacitance and substrate losses, while tuned magnetically induced currents facilitate inductor tunability. The high frequency behavior of the induced current is analyzed, resulting in intuitive insights and design guidelines for a high-performance SSI. An SSI prototype in 65-nm bulk CMOS achieves 34% inductance tunability with a quality factor of >10.3. A voltage-controlled oscillator (VCO) using SSI achieves 40.3% tuning range, from 21 to 31.6 GHz, and a phase noise of −119.1 ± 3.7 dBc/Hz at 10-MHz offset frequencies. The VCO core consumes 4.3 ± 0.2 mW from a 1-V supply.

A 400-mV 2.4-GHz frequency-shift keying transmitter using a capacitor switch across a transformer for a wide tuning range voltage-controlled oscillator

We use a simple directly modulated closed loop to develop a 2.1-mW, 2.4-GHz frequency-shift keying (FSK) transmitter that operates on 400-mV DC supply. Connecting a capacitor bank switch via a transformer in the voltage control oscillator (VCO) to the frequency-divider circuit expands the frequency tuning range without reducing VCO performance. A prototype was fabricated using the 65-nm standard CMOS process with a chip size of 1.65 × 1.85 mm2. A modulation output signal spectrum of −42 dBc at 1.5 MHz with −6 dBm at the PA buffer output terminal; moreover, a VCO phase noise of −101 dBc/Hz at 1 MHz is achieved. The FSK transmitter can readily use voltages supplied by harvested energy because of the low power consumption of the sensor network.

A Low Phase Noise, Low Power and Wide Tuning Range VCO with Filtering Technique in ISM Band

In this paper, a novel voltage controlled oscillator (VCO) with low phase noise, low power consumption and wide tuning range in the industrial, scientific and medical (ISM) band is proposed for communication systems applications. For improving the phase noise, filtering technique is used and VCO is designed with TSMC CMOS 0.18 μm technology and the power supply is 1.5 V. The simulation results with advanced design system (ADS) shows that phase noise in 1 MHz offset frequency from the carrier is -122 dBc/Hz and tuning range is 2 to 2.8 GHz. The power consumption of the core is 2.49 mW.

A Low Phase Noise, Low Power and Wide Tuning Range VCO with Filtering Technique in ISM Band

In this paper, a novel voltage controlled oscillator (VCO) with low phase noise, low power consumption and wide tuning range in the industrial, scientific and medical (ISM) band is proposed for communication systems applications. For improving the phase noise, filtering technique is used and VCO is designed with TSMC CMOS 0.18 μm technology and the power supply is 1.5 V. The simulation results with advanced design system (ADS) shows that phase noise in 1 MHz offset frequency from the carrier is -122 dBc/Hz and tuning range is 2 to 2.8 GHz. The power consumption of the core is 2.49 mW.

A 3.16–7 GHz transformer-based dual-band CMOS VCO**Project supported by the National High Technology Research and Development Program of China (No. 2011AA10305) and the National Natural Science Foundation of China (No. 60901012).

A dual-band, wide tuning range voltage-controlled oscillator that uses transformer-based fourth-order (LC) resonator with a compact common-centric layout is presented. Compared with the traditional wide band (VCO), it can double frequency tuning range without degrading phase noise performance. The relationship between the coupling coefficient of the transformer, selection of frequency bands, and the quality factor at each band is investigated. The transformer used in the resonator is a circular asymmetric concentric topology. Compared with conventional octagon spirals, the proposed circular asymmetric concentric transformer results in a higher quality-factor, and hence a lower oscillator phase noise. The VCO is designed and fabricated in a 0.18-μm CMOS technology and has 75% wide tuning range of 3.16–7.01 GHz. Depending on the oscillation frequency, the VCO current consumption is adjusted from 4.9 to 6.3 mA. The measured phase noises at 1 MHz offset from carrier frequencies of 3.1, 4.5, 5.1, and 6.6 GHz are −122.5, −113.3, −110.1, and −116.8 dBc/Hz, respectively. The chip area, including the pads, is 1.2 × 0.62 mm2 and the supply voltage is 1.8 V.

Ground-Adjustable Inductor for Wide-Tuning VCO Design

A wide-tuning range voltage-controlled oscillator (VCO) with adjustable ground-plate inductor for ultra-wide band (UWB) application is presented in this paper. The VCO was implemented by standard 90nm CMOS process at 1.2V supply voltage and power consumption of 6mW. The tuning range from 13.3 GHz to 15.6 GHz with phase noise between -99.98 and -115dBc/Hz@1MHz is obtained. The output power is around -8.7 to -9.6dBm and chip area of 0.77x0.62mm2.

Low Phase Noise and Wide Tuning Range VCO Using the MOS Differential Amplifier with Active Load

We demonstrate the design of a novel voltage-controlled oscillator (VCO), which is based on a metal-oxide-semiconductor field-effect transistor (MOS) differential amplifier with active load. This VCO achieves low phase noise and wide tuning range. The phase noise is –120 dBc/Hz at 600 KHz offset from a 1.216 GHz carrier frequency. This value is comparable to that of a LC-based integrated oscillator. The operating frequency can be tuned from 117 MHz to 1.216 GHz with the supply voltage varying from 1.3 V to 3.3 V. Therefore, the tuning range is about 90.38% which is larger than most of the LC and ring oscillator. The VCO circuit, which is constructed using a standard 0.35 μm CMOS technology, occupies only 26.25 × 7.52 μm2 die area and dissipated 10.56 mW under a 3.3 V supply voltage.

A 94 GHz Wide Tuning Range SiGe Bipolar VCO Using a Self-Mixing Technique

A self-mixing wide tuning range voltage-controlled oscillator (VCO), using 0.35 μm SiGe bipolar technology, is proposed in this work. The entire circuit consists of a VCO core, a mixer and an emitter coupled differential amplifier. The fundamental and second harmonic signals from the VCO core are used as LO and RF input signals for the mixer circuit, respectively. The mixing product at the third harmonic of the VCO core is selected and amplified, while the low frequency part of the mixing product is suppressed. The simulated harmonic suppression of the third harmonic over fundamental signal is higher than 18 dB. The VCO operates from 91 to 101 GHz with 10.6% tuning range. The measured phase noise at 3 MHz offset is lower than -83 dBc/Hz over the entire frequency band. The VCO occupies 700 × 500 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> die area and consumes 185 mW under 3.5 V dc power supply.

An Integrated Frequency Response Characterization System With a Digital Interface for Analog Testing

Current and future integrated systems demand cost-effective test solutions. In response to that need, this work presents a very compact mixed-signal test system. It performs the characterization of the magnitude and phase responses over frequency at multiple nodes of an analog circuit. The control inputs and output of this system are digital, enabling the test of the analog components in a system-on-chip (SoC) or system-in-package (SiP) through a low-cost digital automatic test equipment. Robust and area-efficient building blocks are proposed for the implementation of the test system, including a linearized analog multiplier for accurate magnitude and phase detection, a wide tuning range voltage-controlled oscillator and a low-power algorithmic analog-to-digital converter. Their individual design considerations and performance results are presented. A complete prototype in TSMC CMOS 0.35-mum technology employs only 0.3mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of area. The operation of this test system is demonstrated by performing frequency response characterizations up to 130 MHz at various nodes of two different fourth-order continuous-time filters integrated in the same chip