一种可植于软件无线电的低功耗可编程增益放大器

本文提出了一种新的技术,用于优化可编程增益放大器的带宽和功耗的关系。这个可编程增益放大器由三级级联的放大器组成,每一级放大器包括可变增益放大器和直流失调电压消除电路。在消除直流失调的电路中,高通的截止频率可从4 kHz到80 kHz变化。可编程增益放大器芯片使用0.13微米的工艺加工,测试结果表明增益可以从-5dB到60dB连续可调。在 60dB增益模式下,当带宽可从1MHz到10MHz变换,电路消耗的功耗为0.85mA到3.2mA,电源电压为1.2V。它的带内OIP3值为14dBm。     

互阻放大器带宽计算方法

互阻放大器是在光电检测前置放大中常用的一种电路结构。在互阻放大器的设计中没有增益带宽积的概念,其带宽分析往往让设计者感到困惑。为了深入研究互阻放大器的增益带宽特性,在此类比增益带宽积的引出,用单极点近似的方法推导出了互阻放大器增益和带宽的关系,并运用Multisim软件进行了仿真,验证了结论的正确性。指出在互阻放大器中增益和带宽仍然是矛盾的,为互阻放大器的带宽设计提供明确的指导。     

一种高性能共模反馈CMOS运算放大器

介绍了一种具有高增益,高电源抑制比(CMRR)和大带宽的两级共源共栅运算放大器。此电路在两级共源共栅运算放大器的基础上增加共模反馈电路,以提高共模抑制比和增加电路的稳定性。电路采用0.35μm标准CMOS工艺库,在Cadence环境下进行仿真。结果显示,该放大器增益可达到101 dB,负载电容为10 pF时,单位增益带宽大约为163 MHz,共模抑制比可达101dB,电路功耗仅为0.5 mW。     

CMOS宽带线性可变增益低噪声放大器设计

文章设计了一种48MHz~860MHz宽带线性可变增益低噪声放大器,该放大器采用信号相加式结构电路、控制信号转换电路和电压并联负反馈技术实现。详细分析了线性增益控制、输入宽带匹配和噪声优化方法。采用TSMC0.18μm RF CMOS工艺对电路进行设计,仿真结果表明,对数增益线性变化范围为-5dB~18dB,最小噪声系数为2.9dB,S11和S22小于-10dB,输入1dB压缩点大于-14.5dBm,在1.8V电源电压下,功耗为45mW。     

全差分增益提高运算放大器的分析与设计

通过增益提高技术,一个全差分增益提高套筒式共源共栅运算放大器被提出和设计。该运算放大器得主运算放大器是由全差分套筒式共源共栅放大器构成,并带有一个开关电容共模反馈电路。而增益提高放大器是由全差分析叠式共源共栅放大器构成,它的共模反馈电路是连续时间反馈电路。该运算放大器采用中芯国际0．35μmixed-signal CMOS工艺设计,运算放大器的直流增益可达到129dB,而单位增益频率为161MHz。     

增益可控低噪声前置放大器设计

设计一种具有温度补偿、增益可控的低噪声前置放大器。该放大器采用级联放大,每一级通过继电器改变信号通路,从而达到控制增益的目的。在放大器的设计中采用噪声抑制和温度补偿技术,并对原电路使用闭环控制进行优化,既实现了增益可调,增益控制范围为10~60 dB,又保证了良好的增益平坦度和优秀的噪声抑制能力。通过仿真和实际电路波形测试,表明该放大器仅有9μV/℃温度漂移和10 nV/Hz~(1/2)等效输入噪声电压,总谐波失真小于1.2%,能放大μV级DC~50 MHz带宽信号。     

一种用于采保电路的宽带高增益放大器的设计

分析了跨导运算放大器的电路结构,采用两级放大电路,考虑到全差分结构中要使用共模反馈,用共源共基和共源共栅电路来实现电路的设计.同时对部分性能指标进行了优化,其中包括增益非线性引入的误差和不完全建立误差.设计了一种宽带高增益跨导放大器,利用0.35 μm Bi CMOS工艺条件下,Spectre仿真得到运算放大器的开环增益大于60 dB,单位增益带宽可达2.1 GHz,输出摆幅能达到1.5 V.     

一种30 dB增益范围的CMOS可变增益放大器

采用0.25μm CMOS工艺设计了一种增益动态范围为30dB的可变增益放大器.该可变增益放大器以Gilbert单元为主体电路,在此基础上采用共源共栅结构,以及电流-电压负反馈的形式,极大地提高了电路的放大增益,并采用共模反馈回路,稳定了高阻输出节点的共模电压,还加入了指数控制电路,使增益与控制电压成dB-线性变化.电源工作电压3.3 V,电路功耗15 mW.     

基于分档切换的射频宽带放大器的设计

针对现行的增益放大器对于低频10M赫兹和高频段的放大特性不能满足增益的一致性,同时每个增益放大器都需级联才能满足0~60d B可调,但级联会产生指标的降低的问题,文中提出一个射频宽带增益放大器。其高频段模块电路是由输入电路、三级16d B放大电路和四选一切换器、增益可调放大器和输出驱动电路组成的模拟电路构成,系统控制模块以STC单片机为主,可完成增益设定、控制四选一切换器、增益可调电路等功能。测试结果表明文中提供的射频宽带放大器,相比传统的射频宽带放大器,在提供较低频段和高频段增益放大且提供增益一致性的同时,能够提供更高的线性度。     

低功耗、高线性度的电流模可编程增益放大器

本文设计了一种电流模式下,带电流模直流失调消除（DCOC）电路的class-AB的可编程增益放大器。电路基于电流放大器,可以实现40dB的增益动态范围,增益步长为1dB。电流模可编程增益放大器由0.18-μm CMOS工艺实现,电路具有较宽的电流增益范围、较低的直流功耗和较小的芯片面积。放大器电路芯片面积为0.099μm2,在1.8V电压下静态电流为2.52mA。测试结果表明电路增益范围为10dB到50dB,增益误差为±0.40dB,OP1dB为11.80dBm到13.71dBm,3dB带宽为22.2MHz到34.7MHz。     

A dual current feedback op amp in CMOS technology

A CMOS circuit configuration implementing a current feedback or transimpedance op amp (CFB op amp) is presented. The architecture of the circuit is derived from similar bipolar CFB op amps. The properties of the CMOS implementation are similar to those of its bipolar counterparts, i.e., a high slew rate and a bandwidth which is independent of the closed-loop gain when the op amp is used with current feedback. Further, it is shown how two CFB op amps can be connected to achieve a non-slew-rate-limited voltage-mode op amp.     

单电源运放的偏置原因分析与偏置方法

运放是模拟电路中的核心元件,近些年来单电源运放因其正常工作时只需提供单路电源的独特优点而应用日益广泛。但是单电源运放的设计却比双电源运放复杂。因此对单电源运放偏置的原因进行了深入的研究,并分析比较了各种不同偏置方法的特点,从而为正确分析和设计单电源运放偏置电路提供依据。     

共源共栅CMOS运算放大器的分析与设计

本文描述了一个共源共栅差分输入级、电流镜偏置输出级结构的两级CMOS运放,它对常规运放的电源电压抑制比、增益、输出驱动能力、噪声、失调等有显著的改善。文中对运放的工作原理及设计技术等进行了详细的叙述,并采用标准CMOS工艺进行了投片试制和采用SPICE进行了电路模拟。结果令人满意,达到了设计指标,证明了设计理论的正确性。该运放已成功地应用于开关电容滤波器芯片的制造。     

Simple technique for op amp continuous-time 1 V supply operation

A simple scheme for achieving continuous-time low-voltage operation of op amps is discussed. The scheme involves placing a floating battery in series with one of the op amp input terminals. Simulations and experimental results are presented that verify the proposed scheme with the example of a CMOS op amp that operates from a single 1 V supply and with 0.8 V signal swing     

Predicting the Effect of Pulsed Ionizing Radiation on Operational Amplifiers

The response of IC operational amplifiers (op amps) to pulsed ionizing irradiation is studied theoretically and experimentally. The major mechanisms of the radiation response are covered. The contributions of main op-amp stages to the output-voltage response are analyzed. The ionization-induced failure of an op amp is traced to its intermediate stages. It is established that the recovery time depends on the type of compensation employed. A block-model approach is proposed as a method for the prediction of transient radiation responses. Ways to define the performance index of an op amp exposed to pulsed ionizing radiation are discussed.     

High-speed GaAs operational amplifier

An operational amplifier has been designed and fabricated using GaAs MESFETs. This amplifier is a general-purpose monolithic GaAs op amp designed as as a stand-alone component. The amplifier has a differential input, an open-loop gain in excess of 60 dB, and is internally compensated. The high open-loop gain (60 dB at 100 kHz) was achieved by using gain stages with positive feedback. The op amp incorporates a current-mirror level-shifting stage which allows the op amp to operate over a wide power-supply range (/spl plusmn/5-9 V). Previous designs have diodes to achieve level shifting, a practice that precludes operation over a wide supply range. This op amp is a true analog to its silicon counterparts, but it has a higher gain-bandwidth product.     

Changing technology-banish the 741! [op amp]

Pick up a current electronics text and you're likely to find the 741 op amp not only used, but also showcased. It's the op amp of choice for lab experiments, treatment of innards, etc. This is truly amazing when you consider that the 741 is nearly 30 years old! Of course op amps should be presented they can be used to implement a remarkable range of circuit functions. An inexpensive op amp can give near-ideal performance in certain practical applications. Getting something to work is infectious-the first op amps gave a whole generation the opportunity to build analog functions that really worked. But, like all technologies, op amp development never ceased; there have been some serious developments over the last 30 years!     

Design for testability of embedded integrated operationalamplifiers

The operational amplifier (op amp) is one of the most encountered analog building blocks. In this paper, the problem of testing an integrated op amp is treated. A new low-cost vectorless test solution, known as oscillation test, is investigated to test the op amp. During the test mode, the op amps are converted to a circuit that oscillates and the oscillation frequency is evaluated to monitor faults. The tolerance band of the oscillation frequency is determined using a Monte Carlo analysis taking into account the nominal tolerance of all important technology and design parameters. Faults in the op amps under test which cause the oscillation frequency to exit the tolerance band can therefore be detected. Some Design for Testability (DfT) rules to rearrange op amps to form oscillators are presented and the related practical problems and limitations are discussed. The oscillation frequency can be easily and precisely evaluated using pure digital circuitry. The simulation and practical implementation results confirm that the presented techniques ensure a high fault coverage with a low area overhead     

A rail-to-rail CMOS op amp

A CMOS op amp (operational amplifier) is reported which has a rail-to-rail voltage range at its input as well as its output. An area-efficient output stage has been used. While the entire op amp occupies only 600 mil², when used as a unity-gain buffer and with ±5-V supplies, the op amp can drive a 9-V_pp/1-kHz sine wave across a 300-Ω load with -64 dB of harmonic distortion     

A 100-MHz 100-dB operational amplifier with multipath nested Millercompensation structure

A 100-MHz bipolar operational amplifier has a gain of 100 dB. The op amp owes its high unity-gain bandwidth and high gain to an all-n-p-n signal path and multipath nested Miller compensation (MNMC). The phase margin with a 100-pF load is 40° at 100 MHz and the amplifier settles in 60 ns to 0.1% on a 1-V step. For comparison, a similar op amp without the multipath technique has been realized. The unity-gain bandwidth of this nested Miller compensation (NMC) op amp is 60 MHz and the settling time is 70 ns. Theory and measurements confirm that the multipath technique almost doubles the bandwidth of nested Miller compensated amplifiers