5-GHz CMOS LC VCOs with wide tuning ranges

A 4.8-GHz LC voltage-controlled oscillator (VCO) optimized for maximum tuning range was designed and fabricated using 0.25-/spl mu/m 1P5M CMOS process. The optimized design used an inverse proportionality between the two parasitic capacitances of the inductor and the MOS transistors for minimizing the parasitic capacitance at the oscillation node. The fabricated LC VCO has a wide tuning range of 20.3% from 4.32 GHz to 5.3 GHz with a power dissipation of 7.3 mW. This tuning range performance is comparable to, or better than, those of the reported CMOS LC VCOs in 5-GHz band. The measured phase noise is -82 dBc/Hz and -114.6 dBc/Hz at 100 KHz and 1-MHz offset, respectively.     

A 0.6 V, 4.32 mW, 68 GHz Low Phase-Noise VCO With Intrinsic-Tuned Technique in 0.13 $mu$m CMOS

An intrinsic-tuned, 68 GHz voltage controlled oscillator (VCO) without an extra on-chip accumulation-mode metal oxide semiconductor (MOS)-varactor is demonstrated in a standard, 0.13 mum CMOS technology. This VCO exhibits phase noises of -98.4 dBc/Hz and -115.2 dBc/Hz at 1 and 10 MHz offset, respectively, along with a tuning range of 4.5 % even under a small power consumption of 4.32 mW. Besides, the highest figure-of-merit (taking frequency tuning range into account) of -182 dBc/Hz under the 1 MHz offset condition is achieved among all previously reported >60 GHz CMOS-based VCOs, which is attributed to the proposed intrinsic tuning mechanism.     

射频卫星电视天线电路中LC压控振荡器设计

本文设计了一款应用于卫星电视天线电路中低功耗、低相噪的宽带单片集成压控振荡器。该振荡器利用PMOS尾电流源和MIM电容阵列结构。在保证调谐范围的前提下,有效的降低了相位噪声。使得该压控振荡器实现了3.384GHz~4.022GHz频段的覆盖,在中心频率为3.7GHz时,100Hz和1MHz频偏处的相位噪声分别为-90.4dBc/Hz和-119.1dBc/Hz,工作电压下为1.8V,功耗仅为2.5mW。     

4GHz级频率综合器下单片低相位噪声CMOS电感电容压控振荡器的设计

基于0.18μm RF CMOS工艺,采用双端调谐结构实现了一种可应用于WLAN的二次变频收发机的压控振荡器.其输出频率范围可以覆盖收发机所需4.1～4.3GHz的频段,其最大调谐范围为500MHz.在距中心频率4.189GHz为4MHz处的相位噪声为-117dBc/Hz,500kHz处为-107dBc/Hz.输出信号抖动的均方根值为4.423ps,输出功率为-8.68dBm.     

SiGe Bipolar VCO With Ultra-Wide Tuning Range at 80 GHz Center Frequency

A SiGe millimeter-wave VCO with a center frequency around 80 GHz and an extremely wide (continuous) tuning range of 24.5 GHz ( ap 30%) is presented. The phase noise at 1 MHz offset is -97 dBc/Hz at the center frequency (and less than -94 dBc/Hz in a frequency range of 21 GHz). The maximum total output power is about 12 dBm. A cascode buffer improves decoupling from the output load at reasonable VCO power consumption (240 mW at 5 V supply voltage). A low-power frequency divider (operating up to 100 GHz) provides, in addition, a divided-by-four signal. As a further intention of this paper, the basic reasons for the limitation of the tuning range in millimeter-wave VCOs are shown and the improvement by using two (instead of one) varactor pairs is demonstrated.     

A /spl Sigma/-/spl Delta/ fractional-N frequency synthesizer using a wide-band integrated VCO and a fast AFC technique for GSM/GPRS/WCDMA applications

A fractional-N frequency synthesizer (FNFS) in a 0.5-/spl mu/m SiGe BiCMOS technology is implemented. In order to operate in a wide-band frequency range, a switched-capacitors bank LC tank voltage-controlled oscillator (VCO) and an adaptive frequency calibration (AFC) technique are used. The measured VCO tuning range is as wide as 600 MHz (40%) from 1.15 to 1.75 GHz with a tuning sensitivity from 5.2 to 17.5 MHz/V. A 3-bit fourth-order /spl Sigma/-/spl Delta/ modulator is used to reduce out-of-band phase noise and to meet a frequency resolution of less than 3 Hz as well as agile switching time. The experimental results show -80 dBc/Hz in-band phase noise within the loop bandwidth of 25 kHz and -129 dBc/Hz out-of-band phase noise at 400-kHz offset frequency. The fractional spurious is less than -70 dBc/Hz at 300-kHz offset frequency and the reference spur is -75 dBc/Hz. The lock time is less than 150 /spl mu/s. The proposed synthesizer consumes 19.5 mA from a single 2.8-V supply voltage and meets the requirements of GSM/GPRS/WCDMA applications.     

A wideband frequency synthesizer for a receiver application at multiple frequencies

An integer-N frequency synthesizer for a receiver application at multiple frequencies was implemented in 0.18 μm IP6M CMOS technology. The synthesizer generates 2.57 GHz, 2.52 GHz, 2.4 GHz and 2.25 GHz local signals for the receiver. A wide-range voltage-controlled oscillator (VCO) based on a reconfigurable LC tank with a binary-weighted switched capacitor array and a switched inductor array is employed to cover the desired frequencies with a sufficient margin. The measured tuning range of the VCO is from 1.76 to 2.59 GHz. From the carriers of 2.57 GHz,2.52 GHz, 2.4 GHz and 2.25 GHz, the measured phase noises are -122.13 dBc/Hz, -122.19 dBc/Hz, -121.8 dBc/Hz and -121.05 dBc/Hz, at 1 MHz offset, respectively. Their in-band phase noises are -80.09 dBc/Hz, -80.29 dBe/Hz,-83.05 dBc/Hz and -86.38 dBc/Hz, respectively. The frequency synthesizer including buffers consumes a total power of 70 Mw from a 2 V power supply. The chip size is 1.5 × 1 mm~2.     

An integrated 8-12 GHz fractional-N frequency synthesizer in SiGe BiCMOS for satellite communications

We present an integrated fractional-N low-noise frequency synthesizer for satellite applications. By using two integrated VCOs and combining digital and analog tuning techniques, a PLL lock range from 8 to 12 GHz is achieved. Due to a small VCO fine tuning gain and optimized charge pump output biasing, the phase noise is low and almost constant over the tuning range. All 16 sub-bands show a tuning range above 900 MHz each, allowing temperature compensation without sub-band switching. This makes the synthesizer robust against variations of the device parameters with process, supply voltage, temperature and aging. The measured phase noise is ?87 dBc/Hz and ?106 dBc/Hz at 10 kHz and 1 MHz offset, respectively. In integer-N mode, phase noise values down to ?98 dBc/Hz at 10 kHz and ?111 dBc/Hz at 1 MHz offset, respectively, were measured.     

An integrated 10 GHz low-noise phase-locked loop with improved PVT tolerance

An integrated phase-locked loop (PLL) with low phase noise is presented, which is robust with respect to variations of device parameters with process, supply voltage, and temperature (PVT). The low-noise CMOS voltage-controlled oscillator (VCO) employs two varactors for fine and coarse tuning. By using a CMOS charge pump with output biasing, the dc fine tuning voltage of the VCO and the loop dynamics of the PLL are well defined and fairly independent of PVT variations. Device noise in the charge pump and linearity of the phase detector are much improved by a two-transistor charge pump architecture for fine tuning. We measured a phase noise below −131 dBc/Hz at 10 MHz offset and below −94 dBc/Hz at 10 kHz offset over a tuning range of 1.2 GHz. An integrated phase error below 0.6° was measured, corresponding to an rms jitter below 160 fs. The chip was produced in a 0.25 μm low-cost SiGe BiCMOS technology, occupies a chip area of 2.25 mm² and draws 60 mA from a 3 V supply.     

Design of wide-band CMOS VCO for multiband wireless LAN applications

In this paper, a general design methodology of low-voltage wide-band voltage-controlled oscillator (VCO) suitable for wireless LAN (WLAN) application is described. The applications of high-quality passives for the resonator are introduced: 1) a single-loop horseshoe inductor with Q > 20 between 2 and 5 GHz for good phase noise performance; and 2) accumulation MOS (AMOS) varactors with C/sub max//C/sub min/ ratio of 6 to provide wide-band tuning capability at low-voltage supply. The adverse effect of AMOS varactors due to high sensitivity is examined. Amendment using bandswitching topology is suggested, and a phase noise improvement of 7 dB is measured to prove the concept. The measured VCO operates on a 1-V supply with a wide tuning range of 58.7% between 3.0 and 5.6 GHz when tuned between /spl plusmn/0.7 V. The phase noise is -120 dBc/Hz at 3.0 GHz, and -114.5 dBc/Hz at 5.6 GHz, with the nominal power dissipation between 2 and 3 mW across the whole tuning range. The best phase noise at 1-MHz offset is -124 dBc/Hz at the frequency of 3 GHz, a supply voltage of 1.4 V, and power dissipation of 8.4 mW. When the supply is reduced to 0.83 V, the VCO dissipates less than 1 mW at 5.6 GHz. Using this design methodology, the feasibility of generating two local oscillator frequencies (2.4-GHz ISM and 5-GHz U-NII) for WLAN transceiver using a single VCO with only one monolithic inductor is demonstrated. The VCO is fabricated in a 0.13-/spl mu/m partially depleted silicon-on-insulator CMOS process.     

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     

The effect of varactor nonlinearity on the phase noise ofcompletely integrated VCOs

This work discusses variations in phase noise over the tuning range of a completely integrated 1.9-GHz differential voltage-controlled oscillator (VCO) fabricated in a 0.5-μm bipolar process with 25-GHz f _t. The design had a phase noise of -103 dBc/Hz at 100 kHz offset at the top of the tuning range, but the noise performance degraded to -96 dBc/Hz at 100 kHz at the bottom of the tuning range. It was determined that nonlinearities of the on-chip varactors, which led to excessively high VCO gain at the bottom of the tuning range, were primarily responsible for this degradation in performance. The VCO has a power output of -5 dBm per side. Calculations predict phase noise with only a small error and provide design insight for minimizing this effect. The oscillator core drew 6.4 mA and the output buffer circuitry drew 6 mA, both from a 3.3-V supply     

基于可变电容反馈技术的宽带VCO设计

该文提出了一种用于展宽Colpitts压控振荡器(VCO)调谐范围(T_R)的技术。为了实现宽调谐范围,采用一种可变电容反馈技术,该技术同时可得到优于传统Colpitts VCO的相位噪声。且该结构采用动态正向衬底自偏技术,以实现VCO较低功耗、易于起振的特性。基于90 nm CMOS工艺,设计了一款VCO,其相位噪声为-101.9 dBc/Hz@1 MHz,调谐范围为28.1%,考虑调谐范围的品质因数可达-192.2 dBc/Hz。芯片在1 V电压供电下,消耗了5.8 mW,芯片面积为0.45 mm~2。     

Dual-band ultra-wide tuning range CMOS voltage-controlled oscillator

A dual-band wide-tuning range LC CMOS voltage controlled oscillator (VCO) topology is proposed. Dual-band operation is realised by employing a double-tuned double-driven transformer as a resonator. The proposed approach eliminates MOS switches, which are typically used in multi-standard oscillators, and thus improves phase noise and tuning range characteristics. The concept is demonstrated through the design of an LC VCO in a standard 0.18 mum CMOS process. Two frequency bands are realised (2.4 and 6 GHz) with 740 MHz tuning range in the first band and 1.56 GHz tuning range in the second band. Operating from a 1.8 V supply, the VCO has a simulated phase noise of -119 dBc/Hz in the 2.4 GHz band and -110 dBc/Hz in the 6 GHz band at 600 KHz offset from the carrier     

A 0.83-2.5-GHz continuously tunable quadrature VCO

A quadrature VCO with /spl plusmn/50% continuous 0.83-2.5-GHz tuning range is presented. It is based on a core LC-QVCO with /spl plusmn/20% tuning range, a single sideband mixer (SSBM), two frequency dividers and a multiplexer. The circuit has been implemented in a 0.13-/spl mu/m 1.2-V CMOS technology. The additional area with respect to the core LC-QVCO is 100 /spl mu/m/spl times/100 /spl mu/m. Quadrature error is less than 2/spl deg/; the phase noise is less than -120 dBc/Hz @ 1 MHz over the whole tuning range and is mainly due to the LC-QVCO. Spurs are more than 34 dB below the fundamental in the worst case.     

A low-noise, 900-MHz VCO in 0.6-μm CMOS

This paper describes a low-noise, 900-MHz, voltage-controlled oscillator (VCO) fabricated in a 0.6-μm CMOS technology. The VCO consists of four-stage fully differential delay cells performing full switching. It utilizes dual-delay path techniques to achieve high oscillation frequency and obtain a wide tuning range. The VCO operates at 750 MHz to 1.2 GHz, and the tuning range is as large as 50%. The measured results of the phase noise are -101 dBc/Hz at 100-kHz offset and -117 dBc/Hz at 600-kHz offset from the carrier frequency. This value is comparable to that of LC-based integrated oscillators. The oscillator consumes 10 mA from a 3.0-V power supply. A prototype frequency synthesizer with the VCO is also implemented in the same technology, and the measured phase noise of the synthesizer is -113 dSc/Hz at 100-kHz offset     

A 900-MHz 1.5-V CMOS voltage-controlled oscillator using switched resonators with a wide tuning range

A 900-MHz fully integrated VCO was fabricated in a 0.18-/spl mu/m foundry CMOS process. Under 1.5 V power supply, this VCO can be tuned from 667 MHz to 1156 MHz which corresponds to a 53.6% tuning range. The VCO has nearly constant phase noise over the whole tuning frequency, credit to the switched resonators used in this VCO. The phase noise at a 600 kHz offset is -123.1 dBc/Hz at 1125 MHz center frequency and -124.2 dBc/Hz at 667 MHz center frequency.     

A GSM-GPRS/UMTS FDD-TDD/WLAN 802.11a-b-g multi-standard carrier generation system

A compact carrier generation system enabling proper interoperability among quad-band GSM, WCDMA (FDD and TDD), and WLAN (802.11a/b/g) standards is developed. The implementation is achieved in 0.25-/spl mu/m BiCMOS-SiGe process. The measured tuning range is higher that 1 GHz (3.05 to 4.1 GHz) exceeding the specifications by 25%. The voltage-controlled oscillator (VCO) exhibits a phase noise of -118 and -125 dBc/Hz measured, respectively, at 400 kHz and 1 MHz offsets while drawing 2.5 mA from 2.5 V supply. The measured phase noise at 400 kHz offset of the PCS/DCS output local-oscillator (LO) signal and the GSM output LO signal is, respectively, -124 dBc/Hz and -130 dBc/Hz.     

Silicon-based distributed voltage-controlled oscillators

Distributed voltage-controlled oscillators (DVCOs) are presented as a new approach to the design of silicon VCOs at microwave frequencies. In this paper, the operation of distributed oscillators is analyzed and the general oscillation condition is derived, resulting in analytical expressions for the frequency and amplitude. Two tuning techniques for DVCOs are demonstrated, namely, the inherent-varactor tuning and delay-balanced current-steering tuning. A complete analysis of the tuning techniques is presented. CMOS and bipolar DVCOs have been designed and fabricated in a 0.35-μm BiCMOS process. A 10-GHz CMOS DVCO achieves a tuning range of 12% (9.3-10.5 GHz) and a phase noise of -103 dBc/Hz at 600 kHz offset from the carrier. The oscillator provides an output power of -4.5 dBm without any buffering, drawing 14 mA of dc current from a 2.5-V power supply. A 12-GHz bipolar DVCO consuming 6 mA from a 2.5-V power supply is also demonstrated. It has a tuning range of 26% with a phase noise of -99 dBc/Hz at 600 kHz offset from the carrier     

A 15-mW fully integrated I/Q synthesizer for Bluetooth in 0.18-/spl mu/m CMOS

A low-power fully integrated synthesizer for Bluetooth applications is presented. The circuit with quadrature output signals at 2.45 GHz and 15-mW power dissipation has been designed in a digital 0.18-/spl mu/m CMOS process with 1.8-V supply voltage. The only external component is a 64-MHz crystal. Measurements have been performed on packaged samples mounted on an FR-4 board and show that the Bluetooth requirements are met. The measured phase noise is below -120 dBc/Hz at 3-MHz offset, and the resulting residual frequency modulation is 7.4-kHz rms. The tuning range consists of an analog and digital tuning mechanism, resulting in more than 15% overall tuning range.