一种低噪声高电源抑制比CMOS低压差线性稳压器

提出了一款基于标准0.18μm CMOS工艺的低噪声高电源抑制比(PSRR)CMOS低压差线性稳压器(LDO),其中包括了带隙基准电路。对LDO和带隙基准电路的噪声和电源抑制进行了建模分析,并得出了电路设计原则。根据设计原则使用两级误差放大器实现了低噪声高电源抑制性能,并且通过合理的频率补偿保证了电路稳定。测试结果显示,LDO输出在-40¹20℃温度范围内的温度系数约为48×10-6/℃;在1120℃温度范围内的温度系数约为48×10-6/℃;在1¹00kHz频率范围内输出噪声电压约为37.3μV;在1kHz和1MHz处的PSRR分别大于60dB和35dB;芯片总面积约为0.27mm2,无负载电流约为169μA。     

一种具有高PSRR的分段温度补偿带隙基准

基于华虹0.18μm BCD工艺,设计了一种具有高PSRR的分段温度补偿带隙基准。电路采用5 V电源进行供电,基准输出电压为1.256 V。仿真结果表明,在-45～125℃的温度范围内,TT工艺角下,传统结构的温漂系数只能达到2.048×10^-5/℃。采用新型分段温度补偿的带隙基准的温漂系数为3.631×10^-6/℃,相比传统结构,温度系数降低了82.3%。静态功耗为220μW。PSRR在低频可达到-102 dB,在350 kHz处有最差PSRR,但仍有-30 dB。该带隙基准适用于高精度、大电流开关电源的模拟集成电路。     

一种高电源抑制比带隙基准电压源的设计

设计了一种基于反馈电路的基准电压电路。通过正、负两路反馈使输出基准电压获得了高交流电源抑制比(PSRR),为后续电路提供了稳定的电压。采用NPN型三极管,有效消除了运放失调电压对带隙基准电压精度产生的影响,并对电路进行温度补偿,大大减小了温漂。整个电路采用0.35μm CMOS工艺实现,通过spectre仿真软件在室温27℃、工作电压为4 V的条件下进行仿真,带隙基准的输出电压为1.28 V,静态电流为2μA,在-20~80℃范围内其温度系数约为18.9×10-6/℃,交流PSRR约为-107 dB。     

一种新颖的无运放高性能带隙基准设计

基于180 nm BCD工艺,在传统带隙基准结构的基础上,设计了一种新型的无运放高性能带隙基准电压源。该带隙基准通过共源共栅电流镜技术和负反馈网络来调节参考电压,消除了运放失调电压的不利影响。电路在Cadence Spectre下仿真。仿真结果表明,设计的输出电压为1.228 V;在-40 ℃至125 ℃的温度范围内,温度系数为1.47×10-6/℃;在1 kHz时的PSRR约为-86 dB;线性调整率为6.5×10-5/V。     

一种新型CMOS带隙基准电压源

传统带隙基准源电路采用PNP型三极管来产生ΔVbe,此结构使运放输入失调电压直接影响输出电压的精度。文章在对传统CMOS带隙电压基准源电路原理的分析基础上,提出了一种综合了一阶温度补偿和双极型带隙基准电路结构优点的高性能带隙基准电压源。采用NPN型三极管产生ΔVbe,消除了运放失调电压影响。该电路结构简洁,电源抑制比高。整个电路采用SMIC 0.18μmCMOS工艺实现。通过Cadence模拟软件进行仿真,带隙基准的输出电压为1.24V,在-40℃~120℃温度范围内其温度系数为30×10-6/℃,电源抑制比(PSRR)为-88 dB,电压拉偏特性为31.2×10-6/V。     

一种带有分段补偿电路的高阶基准源设计

基于SMIC 0.18μm CMOS工艺,设计了一种带分段曲率补偿的低温度系数的高阶带隙基准电压源。首先设计了传统一阶带隙基准,温度系数最低可以达到13×10^-6/℃。在传统一阶带隙基准电压源的基础上,加入低功耗的分段补偿电路实现了高阶补偿,在显著降低了温度系数的同时,实现了低功耗,并且可以实现一阶、高阶基准电压的可控制输出。仿真结果显示,在-40～125℃温度范围内,温度系数最低可以达到3.5×10^-6/℃,比一阶基准降低约73%,线性调整率为0.08%,PSRR在1000 Hz可以达到-61 dB,静态电流为4.7μA。高阶基准源电路在实现低温度系数的同时兼顾了较低功耗,在同类型电路中具有明显优势。     

一种低温漂的无运放带隙基准电压源

针对传统无运放带隙基准电压源温度特性差的问题,设计了一种低温漂的无运放带隙基准电压源电路。设计中通过电流镜以及环路反馈的方法来代替传统运放对电路进行钳位,避免了运放输入失调电压对带隙基准电压精度的影响。同时基于华虹0.35μm BCD工艺,利用工艺库中温度系数不同的电阻来产生与温度相关的非线性项,从而对三极管负温度系数电压中的高阶非线性项进行补偿,实现了无运放带隙基准的低温漂特性。通过Cadence Spectre对电路进行仿真,仿真结果表明：在-55～125℃温度范围内,输入电压为5.5 V时,带隙基准电压的温漂系数为1.949×10^-6/℃;在10 kHz时,电源抑制比达到71.5 dB,在1 MHz时,电源抑制比达到46.3 dB。     

无运放高阶温度补偿的基准电路设计

基于带隙基准源的工作原理以及如何提高温度特性的思想,设计了一种无运算放大器且具有新型高阶温度补偿的带隙基准电路。通过对传统带隙基准电路结构的改进,提出一种新的高阶温度补偿方法。该电路在不使用运放的情况下,分别产生较为精准的正、负温度系数电流,通过共源-共栅电流镜将负温度系数电流降阶,并对其一阶、二阶温度系数进行补偿。电路采用0.18μm CMOS工艺实现,芯片尺寸为240μm×220μm,电源抑制比(PSRR)-64dB。测试结果表明:输出基准电压均值为580.6 mV,在-45~120℃范围内温度系数为7.5×10-6/℃,整个电路的功耗为45μW。     

一种带曲率补偿的低功耗带隙基准设计

为了改善传统带隙基准中运放输入失调影响电压精度和无运放带隙基准电源抑制差的问题,设计了一款基于0.35μm BCD工艺的自偏置无运放带隙基准电路。提出的带隙基准源区别于传统运放箝位,通过负反馈网络输出稳定的基准电压,使其不再受运算放大器输入失调电压的影响;在负反馈环路与共源共栅电流镜的共同作用下,增强了输出基准的抗干扰能力,使得电源抑制能力得到了保证;同时采用指数曲率补偿技术,使得所设计的带隙基准源在宽电压范围内有良好的温度特性;且采用自偏置的方式,降低了静态电流。仿真结果表明,在5 V电源电压下,输出带隙基准电压为1.271 V,在-40～150℃工作温度范围内,温度系数为5.46×10^-6/℃,电源抑制比为-87 dB@DC,静态电流仅为2.3μA。该设计尤其适用于低功耗电源管理芯片。     

一种用于音频Σ-ΔA/D转换器的CMOS带隙电压基准源

在传统带隙基准电压源电路结构的基础上,通过在运放中引入增益提高级,实现了一种用于音频Σ-ΔA/D转换器的CMOS带隙电压基准源。在一阶温度补偿下实现了较高的电源抑制比(PSRR)和较低的温度系数。该电路采用SIMC 0.18-μm CMOS工艺实现。利用Cadence/Spectre仿真器进行仿真,结果表明,在1.8 V电源电压下,-40～125℃范围内,温度系数为9.699 ppm/℃;在27℃下,10 Hz时电源抑制比为90.2 dB,20 kHz时为74.97 dB。     

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.