Temperature compensated and gated CMOS ring oscillator for time-to-digital converter application

This paper presents a CMOS voltage controlled ring oscillator with temperature compensation for low power time-to-digital converters (TDCs). In order to maintain the oscillation frequency stable, a novel compensation circuit is proposed through adaptively sensing temperature variations. This design has been implemented in TSMC 0.35 μm CMOS standard process with an active area of under 0.039 mm². Experimental results show that the clock frequency is around 159.0 MHz only with a power consumption of 550 μA. As respective to the room temperature the maximum frequency variation is between ?3.46 and +3.08 % under temperature range of ?40 to 85 °C. The bit error time induced by clock jitter is limited within 4.8 % in the whole clock period, and the differential nonlinearity of the TDC is less than 0.408 LSB.     

CMOS ring VCO for UHF RFID readers

A complementary metal oxide semiconductor (CMOS) voltage controlled ring oscillator for ultra high frequency (UHF) radio frequency identification (RFID) readers has been realized and characterized. Fabricated in charter 0.35 μm CMOS process, the total chip size is 0.47×0.67 mm2. While excluding the pads, the core area is only 0.15×0.2 mm2. At a supply voltage of 3.3 V, the measured power consumption is 66 mW including the output buffer for 50 Ω testing load. This proposed voltage-controlled ring oscillator exhibits a low phase noise of - 116 dBc/Hz at 10 MHz offset from the center frequency of 922.5 MHz and a lower tuning gain through the use of coarse/fine frequency control.     

A low power consumption CMOS differential-ring VCO for a wireless sensor

This paper describes a new three-stage voltage controlled ring oscillator (VCO) based on 0.35???m standard CMOS technology. The VCO was designed for a transmitter operating in the 863?C870?MHz European band for wireless sensor applications. The transmitter is designed for binary frequency-shift keying (BFSK) modulation, communicating a maximum data rate of 20?kb/s. In addition to the VCO, the transmitter combines a BFSK modulator, an up conversion mixer, a power amplifier and an 863?C870?MHz band pass filter. The modulator uses the frequency hopping spread spectrum and it is intended for short range wireless applications, such as wireless sensor networks. The oscillation frequency of the VCO is controlled by a voltage V_CTRL. Simulation results of the fully differential VCO with positive feedback show that the estimated power consumption, at desired oscillation frequency and under a supply voltage of 3.3?V, is only 7.48?mW. The proposed VCO exhibits a phase noise lower than ?126?dBc/Hz at 10?MHz offset frequency.     

Oscillation-controlled CMOS ring oscillator for wireless sensor systems

This paper presents a ring oscillator with the function of the oscillation controlled for wireless sensor systems (WSSs). The proposed oscillator consists of a NAND gate, 4 inverters, and 1-, 3-, 9-times buffer stage. Operation of it is controlled by the NAND gate. The oscillator can reduce the power loss because the oscillator is oscillated during only high level input. The proposed oscillator was designed and fabricated by 2.5 μm CMOS technology, through which it is possible to realize a WSS on a single chip because a sensor and an oscillator can be fabricated concurrently.The frequency tuning range of the oscillator was found to be approximately 90–152 MHz and the output power of the oscillator was ?8.42 dBm. The measured phase noise is ?99.35 and ?102.59 dBc/Hz at 1 and 5 MHz offsets, respectively, from the carrier of 152 MHz. Power consumption of the oscillator is determined by the duty cycle of the input signal pulse, and the range of power consumption was measured as 1.5–45 mW at the duty cycle of 1.0.     

CMOS RF switched capacitor bandpass filter tuned by ring VCO

A new RF switched capacitor bandpass filter and its command circuit made up of a ring voltage controlled oscillator with ‘XOR’ gates are proposed. Implemented in a standard CMOS technology, this circuit is intended to be used in a subset of professional mobile phone applications [380–520 MHz]. Experiments carried out on a prototype show a tunable center frequency range of 260 MHz [240–500 MHz], with a quality factor that can be as high as 300.     

Low-power CMOS wireless MEMS motion sensor for physiological activity monitoring

In this paper, a short distance wireless sensor node "AccuMicroMotion" for physiological activity monitoring is proposed for detecting motions in six degrees of freedom. System architecture, relevant microstructures, and electronic circuits to implement the sensor node are presented. A three-axis microelectromechanical systems (MEMS) accelerometer and a z-axis gyroscope are designed and fabricated using a new deep-reactive ion-etch CMOS-MEMS process. The interface circuits, an analog-to-digital converter, and a wireless transmitter are designed using Taiwan Semiconductor Manufacturing Company 0.35-/spl mu/m CMOS process, wherein the interface circuits adopt chopper stabilization technique and can resolve a signal (dc to 1 kHz) as low as 200 nV from the microsensors; digitized outputs from the microsensors are transmitted by a 900-MHz amplitude-shift-keying radio-frequency transmitter that delivers a 2.2-mW power to a 50-/spl Omega/ antenna. The system draws an average current of 4.8 mA from a 3-V supply when six sensors are in operation simultaneously and provides an overall 60-dB dynamic range.     

切换式调谐CMOS 压控振荡器

在现有的CMOS RF工艺条件下。利用“切换式调谐”设计思想完成了宽带调谐的压控振荡器(vco)的电路设计和版图设计。用Candence SpectreRF软件进行了模拟。结果表明。该VCO在保证其它性能指标的同时，实现了宽的频率覆盖。     

CMOS temperature sensor with ring oscillator for mobile DRAM self-refresh control

This paper presents novel low-cost CMOS temperature sensor for controlling the self-refresh period of a mobile DRAM. In the proposed temperature sensor, the temperature dependency of poly resistance is used to generate a temperature-dependent bias current, and a ring oscillator driven by this bias current is employed to obtain the digital code pertaining to on-chip temperature. This method is highly area-efficient, simple and easy for IC implementation as compared to traditional temperature sensors based on bandgap reference. The proposed CMOS temperature sensor was fabricated with an 80 nm 3-metal DRAM process, which occupies extremely small silicon area of only about 0.016 mm² with under 1 μW power consumption for providing 0.7 °C effective resolution at 1 sample/s processing rate. This result indicates that as much as 73% area reduction was obtained with improved resolution as compared to the conventional temperature sensor in mobile DRAM.     

A temperature stabilized CMOS VCO

The established method of frequency drift compensation in voltage controlled oscillators (VCOs) resulting from temperature variance involves modulation of control voltage using a non-linear voltage internally generated. An innovative frequency drift compensation scheme for a VCO, based on amplitude control, is described in this paper. Two peak detectors are used to generate voltages representing positive and negative peaks of the sinusoidal driving an error amplifier. The amplifier output controls the delivery of transconductance accessible to the oscillator, thereby keeping the oscillation amplitude steady. Frequency stability has improved to 16 ppm/°C from an uncompensated value of 189 ppm/°C and is applicable where frequency stability requirements are not stringent, such as HS-USB and S-ATA. The temperature stabilized VCO at 2.4 GHz center frequency is prototyped using CMOS technology from ams AG (formerly austriamicrosystems AG). The result obtained from this study indicates that better frequency stability may be achievable if the traditional compensation scheme is preceded by amplitude control.     

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.     

适合宽输出范围频率综合器的CMOS压控振荡器电路

设计了一种基于锁相环宽输出范围(10～160M)的频率综合器,着重介绍了其中的压控振荡器(VCO)部分,采用单端、电流控制型的环振,使之在整个输出范围内,即0～1 20℃、工艺的ss～ffcorner,增益(Kvco.)的变化在3倍以内.无需根据输出频率对电荷泵的充、放电电流或环路滤波器中的电阻作不同设置,环路的衰减因子就可控制在可接受的范围内,并降低了对其它环路参数的要求.设计基于标准0.6μm N-WELL CMOS工艺,5V供电.     

用于数字电视调谐器的宽带CMOS VCO设计

采用片外谐振网络和多VCO的结构设计了一个宽带CMOS VCO,并采用一种新型的电荷泵式自动幅度控制电路,确保了VCO在整个带宽内的可靠性。基于Chartered 0.25μm CMOS工艺的测试结果表明,该VCO的频率能够覆盖75~900 MHz,单边带相位噪声最佳值达到了-92 dBc/Hz@10 kHz。     

Color mixing improvement of CMOS image sensor with air-gap-guard ring in deep-submicrometer CMOS technology

In this letter, color mixings of a CMOS image sensor with air-gap-guard-ring (AGGR) and conventional structures were investigated in 0.18-/spl mu/m CMOS image sensor technology. As the light incident angle is increased from 0/spl deg/ to 15/spl deg/, conventional pixel shows serious color mixing. For example, the maximum photo responses of blue, green1, green2, and red pixels are shifted from 490 to 520 nm, 530 to 500 nm, 530 to 600 nm, and 600 to 580 nm, respectively. However, pixels with AGGR not only keep correct spectral response without peak shift but also achieve 5%-50% crosstalk reduction, thus preventing the sensor from color mixing efficiently.     

Switched inductor dual-band CMOS cross-coupled VCO

This letter proposes a high-performance CMOS dual-band voltage-controlled oscillator (VCO). The VCO consists of two cross-coupled VCOs coupled by a pair of switched inductors or LC resonators to vary the resonator’s inductance. A pair of nMOSFET is used to switch high- and low-frequency bands. The VCO operates at the high-band using low resonator’s inductance and the VCO operates at the low-band using large inductance. The proposed VCO has been implemented with the TSMC 0.18 μm 1P6M CMOS technology and it can generate differential signals in the frequency range of 5.6–6.66 GHz and 4.13–4.75 and it also has comparable high output voltage swings at both low and high-frequency bands. The die area of the dual-band VCO is 0.84 × 1.1 mm². At the supply voltage of 0.75 V, the high (low)-band figure of merit is ?193.6 (?192.3) dBc/Hz.     

输入输出调谐的低相位噪声CMOS压控振荡器

设计了一个输入输出双调谐的CMOS压控振荡器(VCO),与传统的互补型交叉耦合对结构相比,该VCO谐振回路的有载品质因数得到提高,从而降低了相位噪声.采用CSM 0.25μm RF CMOS工艺设计,使用Cadence SpectreRF工具进行了仿真.仿真结果表明在2.5V的电源电压下,调谐范围为2.24～2.58GHz,达到了14.2%,相位噪声为-128dBc/Hz@1MHz,功耗为15mw.     

Fully integrated 10 GHz CMOS VCO

A differential voltage-controlled oscillator has been designed to operate in the 10 GHz band using a 0.25 μm CMOS process and low Q integrated inductors. The low gain and low Q problems of the components are overcome by the deployment of the cascode configuration with negative conductance generation to enhance the loop gain and Q value. PMOS varactors are used for varying the oscillating frequency from 9.7 to 11.4 GHz. The phase noise at 400 kHz offset is from -101 dB/Hz at the low frequency end to -87 dB/Hz at the high frequency end     

新型CMOS正交压控振荡器设计

通过对两个相同的LC振荡器进行交差耦合,用耦合系数来控制输出频率,设计了一种新型精准正交正弦波压控振荡器.由于其频率调节方式不再依赖于变容管,大大增加了输出频率的调节范围.基于TSMC18rf工艺库,采用Cadence的Spectre工具对电路进行仿真.在VDD=1.8V下,频率覆盖了1.78GHz到4.03GHz,可调控范围约为77%,1MHz处相位噪声约为-104dB/Hz.     

Process-and-temperature compensated CMOS voltage-controlled oscillator for clock generators

A voltage-controlled oscillator (VCO) with a current subtraction bias (CSB) for compensating the CMOS process-and-temperature variations is proposed and analysed. The design, fabrication, and testing of a clock generator with a VCO using CSB and conventional fixed bias (FB) is reported. Measurement results demonstrate that the frequency range of CSB selection has 36% reduction against that of FB selection and the temperature coefficient of 76% reduction.     

用于无线通信的CMOS VCO的设计与分析

分析了应用于蓝牙芯片VCO的原理并设计了一种2.5V6mA的低噪声2.1GHzCMOSVCO。通过改变电路结构来改善VCO相位噪声性能。