基于移动设备的D类放大器前置放大器的设计

基于SMIC 0.18μm工艺,设计了一款低功耗、低噪声的D类前置放大器。通过对常用运放的结构进行比较,选择了一种开关电容共模反馈电路的两级运放,并加入斩波结构降低噪声。用Cadence/Spectre仿真器进行仿真,仿真结果表明,该全差分运放的直流开环增益为65 dB,单位增益带宽为259.7 MHz,相位裕度为70°,转换速率为98 V/μs,静态功耗为1 mW。适合于现代的便携产品应用中。     

一种全差动增益增强型跨导运算放大器

设计了一种低电压全差动增益增强CMOS运算跨导放大器。主运放为一个P管输入的折叠式共源共栅结构,两个辅助运放被设计用来提升电路的输出阻抗和开环增益。主运放采用了一种改进的开关电容共模反馈电路,有更快的建立时间和更高的精度。电路采用中芯国际(SMIC)0.18μm混合信号CMOS工艺设计,1.8 V电压供电,仿真结果表明,运算放大器的开环直流增益为92.2 dB,单位增益带宽可达504 MHz。     

Flip-around结构高速采样保持电路的设计

分析了Flip-around结构采样保持电路产生失真的原因。采用增加哑开关管的自举开关,消除与输入有关的电荷注入和时钟馈通;采用增益增强技术,提高运算放大器的直流增益,并通过调整辅助运放的负载电容大小,实现主运放建立时间特性的优化。设计了一个Flip-around结构的高速采样保持电路;对电路各模块进行了功能仿真,给出了整个采样保持电路的仿真结果。     

电流控制型高增益共模反馈电路的设计

介绍了全差分运放的共模反馈原理,并对闭环工作的一级全差分运放结构进行分析,给出了一种电流控制型的高增益共模反馈电路的设计方案。该方案采用标准CMOS0.13μm工艺库,并通过CAD仿真软件验证,结果表明：该共模反馈电路的开环直流增益可达到95dB,补偿后的相位裕度可达到50°,并可在150ns后确保一级全差分运放稳定工作。     

一种全差分增益增强型运算放大器的设计

设计了一种用于高速ADC中的全差分运算放大器。该运算放大器由主运放、4个辅助运放和一种改进型开关电容共模反馈电路组成,主运放采用折叠式共源共栅结构,并引入增益增强技术提高增益。采用SMIC 0.18μm,1.8 V工艺,在Cadence电路设计平台中利用Spectre仿真,结果表明：运放增益达到115 dB,单位增益带宽805 MHz,而功耗仅为10.5 mW,运放在8 ns的时间内可以达到0.01%的建立精度,可用于高速高精度流水线( Pipelined) ADC中。     

一种高性能可编程增益运放电路设计

设计了一种应用于双电源系统的可编程增益运放电路。主要结构包括:偏置电路、控制缓冲电路、主运放电路以及增益控制电路。控制缓冲电路调节电路的工作状态,并且加入传输门模拟开关增加隔离度;偏置电路为控制缓冲电路提供恒定的电流,增强整个电路的稳定性;主运放电路为两级跨导差分结构,采用CSMC 0.5μm ST3000CMOS工艺进行设计,并对电路进行了仿真,其结果显示:开环增益为79 dB,增益带宽为130 MHz,相位裕度为78°,压摆率为756 V·μs~(-1)。基于这种高性能的运放电路,通过接入负反馈电阻分压来实现AV=1或AV=2的增益切换。     

125 kHz RFID反馈系统稳定性的研究

设计了一种射频识别(RFID)收发器模拟前端芯片,可广泛应用于手持终端读卡器等读卡器电子设备.介绍了RFID收发器原理,并在滤波模块设计方面从系统传递函数入手,提出了分析有限增益运放传递函数的4种方法,进而重点分析了考虑寄生参数的实际运放电路两级运放补偿和零点消除技术,并给出滤波电路和采样电路的仿真结果.本芯片采用德国XFAB高压CMOS 0.6um的工艺流片成功,仿真测试结果满足设计要求,系统在各种应用条件和环境下均能正常工作,达到设计要求.     

一款适用于高速读出电路的输出级运算放大器设计

〖JP+1〗CMOS运算放大器是红外探测器系统读出电路的重要模块,其性能直接影响红外读出电路性能。本文设计了一款适用于高速读出电路的输出级运算放大器,在负载电阻100 kΩ,负载电容25 pF的条件下,使读出电路的工作频率大于20 MHz。输出级运算放大器由折叠共源共栅差分运放和甲乙类推挽反相运放级联构成。折叠共源共栅差分运放可以实现电路高增益、大输出电压范围和高输出阻抗,同时可以有效减小放大器输入端的米勒电容效应。甲乙类推挽反相运放具有高电压电流转换效率,可以灵活地从负载得到电流或者向负载提供电流,实现高电流增益,驱动大负载。两级运放之间通过米勒电容实现频率补偿,保证运放的稳定性。本文设计的高速输出级运算放大器基于SMIC 018μm工艺设计,最终实现指标:功耗不大于10mW,运放增益>84dB,相位裕度79°,单位增益带宽>100 MHz,噪声78 μV(1～500 MHz),输出电压范围1～5 V,建立时间<15ns。通过设计高速输出级运算放大器,红外读出电路的读出速率和帧频得到有效提高。     

电感性负载的非福斯特电路研究与设计

基于非福斯特电路的有源电小天线宽带匹配在工程应用领域受到广泛关注。文中以电小环天线的等效电路为负载,提出一种接地型运放管的非福斯特电路,并对其负阻抗转换性能进行了分析。经过仿真分析,在2-30MHz频段内,单级运放非福斯特电路可以实现99%的电感转换率;两级运放乘法电路能够将电路的输入阻抗匹配到50欧姆,S11在整个频段内小于-26dB。实物测试了两级运放乘法器电路,验证了接地型运放管非福斯特匹配电路可较好地提高电感性电小天线的性能。     

一种用于流水线ADC的高速电压比较器

文章介绍了一种高速电压差分比较器电路，该电路采用了两级运放结构。由前置预放大级和带复位端的闩锁输出级组成。该电路采用0．18μm工艺实现，对其进行了电路原理分析和HSHCE仿真。得到的仿真结果和波形说明该比较器具有速度快、精度高、功耗低的特点，适用于流水线结构的高速模数转换器。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks