一种高精度低成本10位D/A转换器的设计与实现

设计了一个采用UMC 0.35μm工艺的高精度、低成本10位D/A转换器电路.该电路对电阻匹配系数要求与7位D/A转换器相同,在相同精度要求下有效减小了版图面积,降低了设计难度和生产成本.最后,在版图上采用新颖的排列方式,进一步减小了温度等因素的影响.该D/A转换器的DNL为-0.2～+0.2,INL为-0.6～+0.6.设计的电路模块已成功应用于商用驱动芯片.     

一种2.5 V 1-MS/s 12位逐次逼近A/D转换器

设计了一种低功耗、中速中精度的单端输入逐次逼近A/D转换器,用于微处理器外围接口。其D/A转换器采用分段电容阵列结构,有利于版图匹配,节省了芯片面积;比较器使用三级前置放大器加锁存器的多级结构,应用了失调校准技术;控制电路协调模拟电路完成逐次逼近的工作过程,并且可以控制整个芯片进入下电模式。整个芯片使用UMC 0.18μm混合模式CMOS工艺设计制造,芯片面积1 400μm×1 030μm。仿真结果显示,设计的逐次逼近A/D转换器可以在2.5 V电压下达到12位精度和1 MS/s采样速率,模拟部分功耗仅为1 mW。     

单片机与串行AD转换器TLC0834的接口设计

TLC0834是TI公司生产的八位逐次逼近模数转换器 ,具有输入可配置的多通道多路器和串行输入方式。文中以AT89C51CPU为核心 ,采用LTC0834八位串行A/D转换器设计了一个可将模拟信号转换为数字信号的电路     

用于便携式设备的12位低功耗SAR A/D转换器

设计了一种适于便携式应用的低功耗12位精度逐次逼近(SAR)式A/D转换器,最高采样频率达到140 KSPS,在1.8 V工作电压下的功耗仅为1 mW;基于0.18 μm 2P4M的CMOS工艺完成版图设计,版图面积仅为0.3 mm×0.35 mm.在转换精度为12位、采样速率为140 KSPS时,A/D转换器的INL和DNL分别为0.7 LSB和0.66 LSB.     

一种采用0.5 μm CMOS工艺的多通道SAR ADC

设计并实现了一个多通道12位逐次逼近(SAR)A/D转换器。转换器内部集成了多路复用器和并行到串行转换寄存器、复合型DAC等。整体电路采用Hspice进行仿真,转换速率为133 ksps,转换时间为7.5μs。通过低功耗设计,工作电流降低为2.48 mA。芯片基于0.5μmCMOS工艺完成版图设计,版图面积为2.4 mm×2.3 mm,流片测试满足设计指标。     

基于嵌入式Linux的A／D转换设备驱动设计

为了满足高精度、高速度的A/D转换应用需求,可以在嵌入式Linux系统中使用ADS7844作为A/D转换器.简述了12位串行A/D转换器ADs7844的结构和工作原理,并且以S3C2410为例介绍嵌入式微处理器外接A/D转换器(ADs7844)硬件电路及其在Linux2.6内核中驱动程序的设计.结果表明ADS7844设备驱动能很好地实现数据采集,并且具有很高的稳定性,ADS7844进行A/D转换速度非常快,精度也很高,达到了设计要求.     

一种轨至轨10位逐次逼近模数转换器的设计

设计了一款用于汽车电子MCU的轨至轨10位逐次逼近A/D转换器。采用单电容采样的DAC结构,保证A/D转换器的全摆幅输入范围。在后仿真验证中,采用频谱分析方法,标定寄生电容对DAC精度的影响,优化了版图结构。设计了片内低压差线性稳压器,提供稳定的电源电压信号。芯片采用GSMC 0.18μm 1P6M CMOS工艺实现。后仿真结果表明,在1.8V电源电压、51kHz输入信号频率、1MHz时钟频率下,无杂散动态范围(SFDR)为73.596dB,有效位数(ENOB)达到9.78位,整体功耗2.24mW,满足汽车电子MCU的应用需求。     

一种基于电流输出DAC的逐次逼近A/D转换器

设计了一种12位逐次逼近A/D转换器.该A/D转换器具有四种信号输入范围,利用电阻网络使不同量程的模拟输入与内部DAC输出范围保持一致,从而使用相同的比较器和基准实现对不同范围输入信号的A/D转换;采用一种新型分段电流源结构,利用电流信号实现内部DAC及逐次比较功能.该电路采用2 μm LC2MOS工艺实现,其积分线性误差(INL)和微分线性误差(DNL)均为±1/2 LSB,最大转换时间为12 μs.     

低功耗10位30MS/s流水线A/D转换器

基于0.18μm CMOS混合信号工艺,设计了一个低功耗10位30 MS/s流水线A/D转换器.通过优化各级采样电容和运放(0TA)偏置电流,以及使用动态比较器,大大降低了整体功耗.采用增益自举开关,以减少开关非线性;引入数字校正技术,以提高转换精度.当采样时钟频率为32 MHz、输入信号频率为16 MHz时,信噪失真比(SNDR)为59 Db,无杂散动态范围(SFDR)为71 Db.AD(:核心电路版图面积为0.64 mm2,功耗仅为32 Mw.     

CS5522型A/D转换器及其在小角度测量中的应用

CS5522是24位高精度△-∑型串行A/D转换器.文中介绍了CS5522型A/D转换器的主要性能、引脚构成、内部寄存器及校准方法.结合CS5522型A/D转换器在小角度测量中的实际应用,给出了CS5522型A/D转换器与单片机的接口及系统电路图,最后给出了试验数据.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

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.     

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.     

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.     

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.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

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.