基于分段电容阵列的改进型逐次逼近型ADC

为缩短高速模数转换器(ADC)中高位(MSB)电容建立时间以及减小功耗,提出了一种基于分段式电容阵列的改进型逐次逼近型(SAR)ADC结构,通过翻转小电容阵列代替翻转大电容阵列以产生高位数字码,并利用180 nm CMOS工艺实现和验证了此ADC结构。该结构一方面可以缩短产生高位数码字过程中的转换时间,提高量化速度;另一方面其可以延长大电容的稳定时间,减小参考电压的负载。通过缩小比较器输入对管的面积以减小寄生电容带来的误差,提升高位数字码的准确度。同时,利用一次性校准技术减小比较器的失配电压。最终,采用180 nm CMOS工艺实现该10 bit SAR ADC,以验证该改进型结构。结果表明,在1.8 V电源电压、780μW功耗、有电路噪声和电容失配情况下,该改进型SAR ADC得到了58.0 dB的信噪失真比(SNDR)。     

高精度离散型Sigma delta调制器设计

阐述一种采用SAR ADC作为多位量化器的三阶离散时间（DT）Sigma delta ADC调制器,在该调制器中,量化器由4位SAR ADC构成,相比于传统Flash ADC类型的量化器,减少了比较器的个数的同时,降低了调制器整体功耗。调制器结构选择单环CIFF结构兼顾了电路的精度和稳定性,电路总体采用分级结构实现,在第一级积分器中加入斩波稳定技术,消除低频噪声的干扰。提出的离散型Sigma delta ADC调制器采用TSMC 0.18μm CMOS工艺设计,在20kHz带宽实现了104.9dB的峰值信噪谐波失真比（SNDR）,功耗为5.98mW,有效位数(ENOB)为17.13位。     

7位80MS/s电流模式折叠分级式模数转换器

提出了一种基于电流模式的折叠分级式A/D转换器(ADC),分析了电路原理和结构,阐述了如何提高ADC的性能。测试表明,电路已达到相关性能指标。转换速率为80MS/s,在3.0MHz输入信号下的信噪失真比(SINAD)为44.4dB,有效位数(ENOB)为7.1位。给出了已实现ADC电路的结构、测试波形和动态性能测试结果。     

二阶误差反馈型失配误差整形16位500 kS/s SAR ADC

为了解决高精度逐次逼近型模数转换器(SAR ADC)中电容失配对精度的影响,设计了一种二阶误差反馈型失配误差整形(EFMES)16位精度、500 kS/s采样率、3.3 V工作电压的SAR ADC。采用二阶EFMES结构和动态元件匹配技术,降低了电容失配对ADC精度的影响。该EFMES SAR ADC采用SMIC 0.18 μm CMOS工艺设计。在输入信号幅度为2.6 V、采样率为500 kS/s时,该ADC的功耗为8.382 mW,SNDR为93.67 dB,ENOB为15.27位,基于SNDR的FoM为168.4 dB。     

一种基于CMOS工艺的异步数字斜坡ADC

设计了一个5位330 MS/s的异步数字斜坡模数转换器(ADC)。采用中芯国际55 nm工艺和Cadence Virtuoso软件,对电路进行设计和仿真。供电电源为1.2 V,改进后的延迟单元将延迟时间缩短到50 ps。另外,该电路中的比较器采用自动关闭方式,节省了功耗。输入电压峰峰值为0.4 V时,仿真得到信噪失真比(SNDR)为28.19 dB,有效位(ENOB)为4.39位,无杂散噪声动态范围(SFDR)为35.87 dB,信噪比(SNR)为31.47 dB。     

一种低功耗8位300MS/s异步SAR ADC

设计了一种单循环8位300 MS/s低功耗异步SAR ADC。设计基于内部时钟电路,实现异步算法,使得ADC整体速度得到提升。采用分裂式顶端采样DAC阵列、高速比较器、自举开关以及低功耗动态逻辑单元,使得电路在高速转换下可以保持低功耗。基于SMIC 65 nm工艺实现,在1.2V电源电压以及300 MS/s的采样频率下,总功耗为0.84 m W。ADC的信噪失真比(SNDR)达到47.9 d B,有效位数(ENOB)达到7.6位,品质因数为16.6 f J/Conv。     

一种基于电压窗口技术的超低功耗SAR ADC

本文提出了一种应用于生物医学的超低功耗逐次逼近型模数转换器(SAR ADC).针对SAR ADC主要模块进行超低功耗设计.数模转换(DAC)电路采用vcm-based以及分段电容阵列结构来减小其总电容,从而降低了DAC功耗.同时提出了电压窗口的方法在不降低比较器精度的情况下减小其功耗.此外,采用堆栈以及多阈值晶体管结构来减小低频下的漏电流.在55nm工艺下进行设计和仿真,在0.6V电源电压以及l0kS/s的采样频率下,ADC的信噪失真比(SNDR)为73.3dB,总功耗为432nW,品质因数(FOM)为11.4fJ/Conv.     

一种实现2倍无源增益的噪声整形SAR ADC

设计了一种采用65 nm CMOS工艺的无源噪声整形SAR ADC电路。该电路在SAR ADC的基础上仅增加6个开关和2个电容,以实现噪声整形,整体电路结构简单,有效提高了SAR ADC精度。此外,实现了2倍的无源增益,增强了对比较器噪声的抑制作用。构建具有良好噪声抑制效果的噪声传递函数,避免使用残差采样模块和多路比较器。仿真结果表明,设计的10位噪声整形SAR ADC电路在33.3 MHz采样率、2.08 MHz带宽、1.2 V输入电压的情况下,有效位数达12.4位,功耗为459 μW。     

一种应用于WLAN标准的改进型低失真sigma-deltaADC设计

提出了一种应用于WLAN(无线本地局域网)标准的改进型低失真sigma-delta模数转换器(ADC)设计。采用前馈多位级联2-2sigma-delta ADC架构,通过在第二级增加反馈因子,信号带内增加零点的方法,提高了ADC带内信噪失真比(SNDR)。同时,使用数据权重平均(DWA)技术以减小多位数模转换器(multi-bit DAC)的失配噪声,提高整体ADC的无杂波动态范围(SFDR)。采用0.18um CMOS工艺实现,1.8V电压供电,测试结果显示,采样频率为160MHz时,对于1.25MHz@-6dBFS的输入信号,SNDR峰值为80dB,SFDR为87dB,有效位数(ENOB)为13.15位,较之以往所提出的的低失真sigma-delta ADC具有更好的性能。     

一种基于EF和CIFF的10 bit二阶噪声整形SAR ADC

设计了一种10 bit阶噪声整形的逐次逼近型模数转换器(NS-SAR ADC)。为了减小高精度SAR ADC中量化噪声的影响,该NS-SAR ADC采用了级联积分器前馈(CIFF)与误差反馈(EF)相结合的噪声整形方案。其中EF路径采用低增益动态放大器构成的无损积分架构,CIFF路径采用电压倍增的无源整形架构。它结合了CIFF与EF两种噪声整形架构的优点,具有更好的鲁棒性。电路采用TSMC 65 nm CMOS工艺设计,在电源电压为1.2 V、输入信号幅度为1 V、采样率为25 MHz的条件下,SNDR达到77.91 dB,带宽BW为1.562 5 MHz,功耗为465 μW。     

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.