用于16位流水线ADC的高速动态比较器设计

介绍一种用于16位100MS/s流水线ADC中第一级子ADC的开关电容高速动态比较器电路,在传统的前置放大器加锁存比较电路结构的基础上,设计再生比较器的复位信号,增加失调消除反馈环路,当输入信号在各基准电压判定点附近一定范围内时交叉输出0、1电平,一方面均衡噪声,另一方面消除因工艺制造失配等带来的失调误差的影响。电路采用0.18μm 1.8V1P5MCMOS工艺,在1.8V条件下传输延时约300ps,转换速率约100ps,功耗约250μA,失调电压仅约0.2mV,可以满足16位流水线ADC对比较器性能的要求。     

用于高速电荷域ADC的电荷比较器设计

设计了一种用于电荷域流水线ADC的高速电荷比较器电路,该比较器包括电荷采样电路、共模不敏感开关电容网络和锁存放大器。仿真结果表明,在0.18μm CMOS工艺条件下,该比较器在250 MHz时钟下性能良好,采用该比较器的12位250 MS/s电荷域ADC内的2.5位子级电路功能正确。     

10 bit 80 Msample/s流水线ADC的电路级设计

实现了0.18μmCMOS模拟工艺、1.8V电源电压下10位分辨率、80MHz采样率的流水线ADC的电路级设计,采用栅压自举的采样开关和增益提升运放保证ADC的精度;采用复位结构的SHC和MDAC消除运放失调电压的影响;采用动态比较器并优化每级电容以降低功耗.当输入信号幅度为1Vpp时,ADC在整个量化范围内无失码,当输入信号频率为39MHz时,可获得71.6dB的无失真动态范围和60.56dB的信噪失真比.     

一种流水线A/D转换器Multi-bit级增益误差校正方法

提出了一种用于流水线A/D转换器multi-bit级增益误差校正的方法及其实现方案.该方法应用改进冗余位结构,通过在其子DAC输出端引入伪随机信号测量级间增益;利用此估计值在后台进行增益误差补偿.为了验证设计,对12位流水线ADC进行系统模拟,当首级有效精度为3位,且相对增益误差为±2%时,经校正后,INL均为0.16 LSB,DNL分别为0.13 LSB和0.14LSB,SFDR和SNDR分别提高35 dB和16 dB.分析表明,该方法能有效补偿multi-bit级增益偏大或偏小的误差,进而实现增益误差校正,且不会降低ADC转换范围和增加额外的比较器.     

用于视频图像传感器的12 bit 60 MS/s流水线模数转换器

介绍了一种12 bit 60 MS/s流水线模数转换器(ADC),该转换器使用采样保持电路,将连续变化的模拟信号通过一定时间间隔的采样,以实现信号的准确量化,利用增益自举运放提高信号建立的线性度;采用每级1.5 bit精确度的流水线结构实现冗余编码,降低比较器失调电压对精确度的影响,同时提出一种新型的消除静态功耗的预放大比较器结构。该流水线ADC芯片采用华力55 nm 互补金属氧化物(CMOS)工艺进行电路和版图设计。对后仿真结果进行快速傅里叶变换(FFT)分析得到：动态参数无杂散动态范围(SFDR)为86.18 dB,信噪比(SNR)为72.91 dB,信纳比(SNDR)为72.8 dB,有效位数(ENOB)为11.72 bit。     

一种流水线ADC级间增益非线性误差的数字域补偿方法

基于流水线ADC(模数转换器)结构中级间残差放大器的增益压缩特性,合理地将其建模为奇数次幂级数形式,详细描述并分析确定了它产生的非线性失真对ADC性能的影响方式与权重.针对性地提出了数字域反向抵消方案,通过引入数字伪随机序列的方式,利用二阶统计互相关的信息自适应地辨识与逼近实际模型系数,并采用此估计值在后台实现级间增益非线性补偿过程.对14位三级流水线ADC进行系统模拟,当前两级量化精度为5位,且两级残差放大器的输出峰值点的相对增益压缩率均为5%时,经过补偿后,SFDR(无杂散失真动态范围)和SNDR(信噪失真比)指标分别从67.84dB、51.26dB提高到94.16dB、72.97dB.该方法为高精度流水线ADC的设计提供了可供参考的结论和技术解决方案.     

基于冗余子级的流水线ADC校准技术

提出了基于冗余子级的流水线ADC后端校准技术,采用精度较高的流水线冗余子级代替参考ADC,对流水线ADC的各个子级校准,替代了对整个ADC的校准,使校准系统无需降频同步,较好地解决了传统校准系统中主信号通路与参考ADC信号通路不同步的问题。对Matlab/Simulink中搭建的精度为16位、采样频率为10 MS/s的流水线ADC进行仿真,结果表明,当输入信号频率为4.760 5 MHz时,经过校准,流水线ADC的有效位和无杂散动态范围分别由9.37位和59.96 dB提高到15.32位和99.55 dB。进一步的FPGA硬件验证结果表明,流水线ADC的有效位和无杂散动态范围分别为12.73位和98.62 dB,初步验证了该校准算法的可行性。     

一种用于12位250MSPS流水线ADC的中频采样前端

设计了一种具有中频采样功能的流水线ADC采样保持前端电路.采样保持前端电路采用基于开关电容的底板采样翻转式结构,运算放大器采用了米勒补偿型两级结构以提高信号摆幅,采样开关采用了消除衬底偏置效应的自举开关以提高中频采样特性.该采样保持前端电路被运用于一种12位250 MSPS流水线ADC,电路采用0.18μm lP5M 1.8 V CMOS工艺实现,测试结果表明该ADC电路在全速采样条件下对于20 MHz的输入信号得到的SNR为69.92 dB,SFDR为81.17 dB,-3 dB带宽达700 MHz以上,整个前端电路的功耗为58 mW.     

一种12位50MS/s CMOS流水线A/D转换器

采用TSMC 0.18μm 1P6M工艺设计了一个12位50 MS/s流水线A/D转换器（ADC）。为了减小失真和降低功耗,该ADC利用余量增益放大电路（MDAC）内建的采样保持功能,去掉了传统的前端采样保持电路;采用时间常数匹配技术,保证输入高频信号时,ADC依然能有较好的线性度;利用数字校正电路降低了ADC对比较器失调的敏感性。使用Cadence Spectre对电路进行仿真。结果表明,输入耐奎斯特频率的信号时,电路SNDR达到72.19 dB,SFDR达到88.23 dB。当输入频率为50 MHz的信号时,SFDR依然有80.51 dB。使用1.8 V电源电压供电,在50 MHz采样率下,ADC功耗为128 mW。     

用于12位250 MS/s电荷域ADC的2.5位子级电路

提出了一种用于12位250 MS/s电荷域流水线模数转换器(ADC)的2.5位子级电路。采用增强型电荷传输电路,实现电荷传输和余量电荷计算,省去了传统流水线ADC中的高性能运放,大幅降低了ADC的功耗。该2.5位子级电路被应用于一种12位250 MS/s电荷域流水线ADC中,并采用0.18 μm CMOS工艺实现。测试结果表明,在250 MS/s采样率、20.1 MHz输入频率下,该ADC的SNR为65.3 dBFS。     

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.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

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.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.