一种高线性低功耗基带Gm-C滤波器

介绍了一种应用于无线局域网(WLAN)收发机系统的跨导-电容(Gm-C)低通滤波器,该电路可工作于低电压,并且具有高线性度.该射频发射器中的滤波器采用截止频率为9.9 MHz的3阶切比雪夫低通滤波器,在30 MHz频率处的阻带衰减达到30.5 dB.由于采用跨导线性环技术,滤波器工作于1.2V电源电压时,IIP3可达13.5 dBm.电路采用0.13 μm CMOS工艺实现,滤波器芯片尺寸为0.52 mm×0.17 mm,消耗电流3.76 mA.     

高频高线性度跨导电容滤波器

为了提高滤波器的工作频率和线性度,提出一种新型跨导放大器。该跨导器采用差分和交叉耦合来改善跨导输入级直流传输特性的线性度,以及扩大输入电压允许范围;同时,为了稳定输出共模电平和增大动态范围,提出共模反馈电路和各支路增益调整方法。对该滤波器进行理论分析和验证,结果表明,Gm-C滤波器的截止频率为159.6MHz,过渡带宽大于45dB,动态范围为64dB,具有较好的高频和高线性度特性。     

一种高线性度低失真跨导运算放大器的设计

为了解决线性跨导输入范围有限的问题,提出了一种具有宽线性输入范围的高线性运算跨导放大器(Operational Transconductance Amplifier,OTA),可有效适用于包括低频连续时间滤波器在内的电流模式电路。该OTA利用源极退化和辅助差分结构,通过减少失真分量来显著增加线性范围。此外还利用该OTA实现了一种二阶全差分滤波器;采用SCL180 nm CMOS工艺进行了设计和仿真。实验结果表明,相比于其他设计方法,该OTA和滤波器具有更宽的线性范围和更低的失真。对于1 MHz信号频率、600 mVP-P的输入,该OTA的三次谐波失真分量和互调失真分量分别为-74.8 dB和-76.1 dB,线性范围为0.9V(1%跨导变化)。对于300 mVP-P、10 kHz输入,该滤波器的三次谐波失真分量和互调失真分量分别为-69.75 dB和-65.2 dB。     

低功耗跨导-电容滤波器及其调谐电路的设计

设计了一种以Nauta跨导为单元结构的5阶切比雪夫跨导-电容带通滤波器及其调谐电路.该电路应用于低中频结构的北斗卫星导航接收机射频前端.滤波器的中心频率为4.092MHz,带宽设计为±2.046 MHz.该滤波器采用锁相环结构的片上自动频率调谐电路,用TSMC0.13 μm RF CMOS工艺实现,芯片面积仅为0.24 mm2,可以在低电压下工作,电路总功耗仅为1.68 mW.     

蓝牙芯片发送通道的OTA-C连续时间型模拟滤波器设计

文章通过对低通滤波器的设计,主要讨论分析了跨导放大器一电容(OTA-C)连续时间型滤波器的结构、性能、设计和具体的实现方法,并利用Cadence软件进行了仿真验证.仿真结果说明OTA-C滤波器是一种便于设计实现、适合处理高频模拟信号并可实现完全集成的滤波,在模拟信号处理方面拥有可观的发展前景和潜力.针对滤波结构中跨导放大器(OTA)线性度不高的情况,通过改变结构,增加了线性调整对管提高了线性度,并通过仿真结果证明了其性能改善的情况.     

一种高线性Gm-C复数滤波器的设计

针对低电源电压Gm-C复数滤波器线性度不足的问题,提出了一种使用大信号线性化技术的一阶复数带通滤波器。所提出的复数滤波器使用了不平衡差分对和自适应偏置电路两种线性化技术,通过扩展跨导相对恒定的输入电压范围提高滤波器的线性度。滤波器采用UMC 110 nm CMOS工艺设计,中心频率和带宽分别为2 MHz和1 MHz。Cadence仿真结果显示,在1.2 V电源电压下,滤波器功耗为229μW,镜像抑制比(IIR)为18 dB,线性度(输入三阶交调点IIP3)为9.53 dBm,总谐波失真(THD)为-55.7 dB。该复数滤波器电路结构简单、功耗较低,以期能广泛应用于低电源电压的接收机设计。     

0.13 μm CMOS宽带大动态范围六阶跨导电容低通滤波器

提出了一种适用于宽带大动态范围应用的六阶跨导电容低通滤波器。该滤波器为Chebyshev类型,采用开环级联结构来实现。通过一组开关电容阵列来补偿由工艺温度等因素引入的截止频率的偏差。实际测试结果表明,该滤波器的-3dB截止频率可调范围为30～100MHz,在500mVp-p输入信号幅度下,IM3为-48dB。电源电压为3V时,消耗电流25mA,芯片面积为0.5mm2。该滤波器采用TSMC0.13μm CMOS工艺实现。     

应用于直接变频架构直播卫星调谐器中的具有宽调谐范围的连续时间低通滤波器

本文用0.35微米锗硅BiCMOS工艺设计了七阶巴特沃兹跨导电容低通滤波器及其片上自动调谐电路,该低通滤波器适用于采用直接变频架构的直播卫星调谐器。该滤波器的-3dB带宽截止频率具有从4MHz到40MHz的宽调谐范围。成功实现了一种新颖的片上自动调谐方案,用来调谐和锁定滤波器的-3dB带宽截止频率。测试结果表明,该滤波器具有-0.5dB的通带电压增益,+/- 5%的带宽精度,30nV/Hz1/2的等效输入噪声,-3dBVrms 通带电压三阶交调点,27dBVrms 阻带电压三阶交调点。I/Q正交两路滤波器及其调谐电路采用5V电源,在滤波器的-3dB带宽截止频率为20MHz的情况下,消耗电流13毫安,占用芯片面积0.5mm2。     

一种适用于生物电信号处理的全集成五阶Gm-C低通滤波器

传统的Gm-C滤波器OTA输入晶体管大多工作在饱和区,存在输入动态范围较小和跨导值较大等不足,难以满足生物医学电信号处理滤波器所要求的超低截止频率、低功耗与大输入动态范围等要求,采用将输入晶体管钳位到线性工作区的方法,设计了跨导线性可调的OTA以提高滤波器能够处理的信号幅度。并应用该OTA综合了一种五阶Gm-C超低频低通滤波器。仿真结果表明,该滤波器在1.8 V电源,800 m Vpp输入条件下实现了283 Hz的超低低通角频率,-6.4 d B的带内增益,51 d B的三次谐波失真,功耗仅为22μW,适用于可穿戴式生物医学电信号读取电路。     

一种低功耗线性范围宽的跨导放大器及其在滤波器中的应用

本文分析了以往文献中提出的各类跨导放大器(OTA,operational transconductor amplifier)的结构特点,为了能更好地改善线性度并降低功耗,本文提出了一种全差分带电流负反馈的跨导放大器。在1.5V的电源电压下,经cadence仿真平台验证,该跨导放大器的线性范围拓宽到1V,IIP3达到24.80dBm,功耗低于14μW。将此跨导放大器应用到三阶椭圆低通跨导电容(OTA-C)滤波器中,经cadence仿真验证,该滤波器的幅频特性陡峭,IIP3达到13.51dBm,功耗为1.6mW。     

A New CMOS Programmable Balanced Output Transconductor and Application to a Mixed Mode Universal Filter Suitable for VLSI

A new CMOS programmable balanced output transconductor (BOTA) is introduced. The BOTA is a useful block for continuous-time analog signal processing. A new CMOS realization based on MOS transistors operating in the saturation region is given. Application of the BOTA in realizing a mixed mode universal filter using six BOTAs and two grounded capacitors is also introduced. The filter's gain can be adjusted simply by varying the amplitude of a transconductance through its control voltage without affecting ₀ and Q of the filter. Also, the Q of the filter can be adjusted by a single transconductor independent of ₀. PSpice simulation results for the BOTA circuit and for the universal filter are also given.     

High Linearity BiCMOS Multiplier/Transconductor Structures

A new wide-input range BiCMOS analog multiplier is proposed basedon the triode and saturation region operation of the MOS transistors. Thenew circuit can also be reconfigured to operate as a versatile OperationalTransconductance Amplifier, OTA, with independent current bias control for Nstages. The novel design involves the use of attenuators at the input stageto boost the input linear range. It also utilizes a high output impedancesubtractor setup at the output stage to obtain a single-ended output. Thenew circuit is characterized by its large input range, its high linearityand ability to operate at low voltages as well as high frequencies. HSPICEsimulation results of the circuit, using the MOSIS 2 µm processparameters, resulted in an input range of ±4 V (±5 V supply),±1.9 V (±3 V supply) and ±1 V (±2 V supply),with linearity error less than 0.5%. Its usages in certainanalog signal processing applications are also discussed.     

A highly linear baseband G_m-C filter for WLAN application

A low voltage,highly linear transconductance-C（G_m-C） low-pass filter for wireless local area network （WLAN） transceiver application is proposed.This transmitter（Tx） filter adopts a 9.8 MHz 3rd-order Chebyshev low pass prototype and achieves 35 dB stop-band attenuation at 30 MHz frequency.By utilizing pseudo-differential linear-region MOS transconductors,the filter IIP₃ is measured to be as high as 9.5 dBm.Fabricated in a 0.35μm standard CMOS technology,the proposed filter chip occupies a 0.41×0.17 mm² die area and consumes 3.36 mA from a 3.3-V power supply.     

A technique to compensate an influence of mobility degradation by combining a source coupled pair with a transconductor

A transconductor is a basic building for integrated analogue circuits. High linearity of the transfer characteristic is necessary to a transconductor. However, along with miniaturisation of a device, linearity of the transconductor has deteriorated because of the mobility degradation from an effect of a vertical electric field. This paper proposes a new technique to reduce the influence of mobility degradation and to improve linearity of a transconductor. In order to improve the linearity, a source-coupled pair is combined with the transconductor. It is confirmed that the proposed technique reduces the transconductance error by about 1/5. For a sinusoidal input voltage of 1 V_p-p and 1 MHz, the total harmonic distortion is 3% or less.     

Low-Voltage Rail-to-Rail Tunable FGMOS Transconductor

A compact, tunable CMOS transconductor is presented. The combined use of a Floating-Gate MOS (FGMOS) differential pair and a floating DC level shifter allows the use of low supply volatages while maintaining at the same time a rail-to-rail input range, low distortion and high linearity. Measurement results for a prototype fabricated using a 0.8 m CMOS technology are provided, confirming on silicon the validity of the proposed approach.     

Multifunctional adjustable current mode biquads based on distributed feedback voltage mode prototype with OTAs

This article deals with electronic adjustable active RC biquads working in current mode (CM), using transconductors (OTAs), with a single input and single or dual outputs. Transformation of known voltage mode (VM) filter prototype into CM and subsequent modifications is given to obtain new active filtering circuits. The characteristics of the given circuits are verified by simulations of the OTAs at the transistor level using PSpice. The measurement results support the computer simulations.     

Large Dynamic Range High Frequency Fully Differential CMOS Transconductance Amplifier

A large dynamic range high frequency fully differential CMOS transconductance amplifier is introduced. It is based on the linear transconductance element proposed in [8] combined with the common-mode feedback circuit in [9]. The original transconductance and common-mode circuits which use two supply voltages are modified for operation under a single power supply. The performance of the complete transconductance amplifier is analysed in details. Simulation results of the whole circuit are also presented, which show that with a single 5 V supply, bandwidth in excess of 300 MHz, THD below 0.7% for a 1 V _pk–pk differential input signal, and dynamic range in excess of 70 dB can be achieved for the fully differential transconductance amplifier.     

High-efficiency bipolar transconductors composed of hyperbolic function circuits with an intermediate voltage terminal and a triple-tail cell

Relatively high transconductance in bipolar devices contributes to the economy of power dissipation on analog integrated circuits. Recently, a high-speed transistor, such as the HBT attracts attention of researchers and developers in electronic communication industries and is expected to be applied to RF circuits. In this paper, high-efficiency bipolar transconductors are presented. The proposed circuits are composed of a hyperbolic function circuit with an intermediate voltage terminal and a triple-tail cell. The parameter values for linearisation are all integers. The values can be realised precisely. The linearity of the proposed transconductors is superior to the triple-tail cell. The linear input range is 1.5 times as wide as that of the conventional triple-tail cell. Nevertheless, the power dissipation is lower than the triple-tail cell. Further, sensitivity analysis shows that the proposed transconductors have lower sensitivity than the triple-tail cell. These properties are confirmed by SPICE simulation.     

A novel CMOS exponential transconductor operating in weak inversion

A novel CMOS exponential transconductor which employs only three NMOS transistors operating in weak inversion, is presented. The main advantage of the proposed circuit is its wide range of exponential behaviour, which reaches up to five decades of current range, and above 10 μA to an input voltage range of 800 mV. The physical realisation is achieved in two forms: in the first one, the circuit is implemented with discrete MOS transistor arrays by CD4007 series; in the second one, the circuit is fully integrated in a 0.5 μm CMOS standard process. Simulated and experimental results of the proposed exponential transconductor are also presented.     

Li_2分子A~1Σ_u~+→X~1Σ_g~+LIF和b~3Ⅱ_u→X~1Σ_g~+CIF发射光谱研究

用632.8nm CW激光获得了Li_2分子A~1∑_u~+(v′=15,J′=2)→X~1∑_g~+(v″=1～13,J″=1,3)R、P支双线LIF光谱。同时用光谱分析及碰撞动力学研究识别出另一支单线序列光谱来自b~3Ⅱ_u(v_b=21,N_b=1)→X~1∑_g~+(v″=3～6,J″=1)CIF发射。