基于二分法的混合信号接口板的设计

介绍了一种基于二分算法的混合信号接口板.该接口板可通过编程任意配置测试芯片管脚实现模拟或数字信号输入端口与输出端口的无损连接,可广泛应用于芯片自动化测试领域.本设计采用二分法来实现管脚的分级,采用遍历引脚逐一比较的方式来配置引脚连接,通过控制模拟开关阵列来实现模拟信号的输入与输出端口连接,通过FPGA实现数字信号的输入与输出端口连接.该设计方案利用极少的开关实现了复杂线路的配置,具有较高的资源利用率,极大降低了芯片测试的难度和成本.     

用于反熔丝FPGA的多标准IO接口电路

针对高可靠性领域和复杂环境对大规模反熔丝FPGA器件的迫切需求,设计了一种新的用于反熔丝FPGA的可动态配置IO接口电路。该IO接口电路具有宽的输入输出电压范围,能实现多驱动调节,支持一系列不同电平模式。通过对反熔丝单元进行编程配置,该IO接口电路可兼容多种IO标准,内核电压为2.5 V,端口电压可在3.3 V与5 V之间转换。仿真与测试结果表明,该IO接口电路满足设计要求,接口速度优于国外同类产品。     

65nm CMOS工艺中的高速多标准FPGA I/O接口设计

设计了一种现场可编程门阵列(FPGA)中使用的高速可配置的输入输出(I/O)接口电路。通过使用电平移位电路、互补自偏置差分放大电路(CSDA)等,该电路实现了包括低压差分信号(LVDS)在内的多种常见的接口协议标准。该电路同时具备可编程配置压摆率和可编程配置输出驱动电流的功能,同时为保证信号完整性,设计了数字阻抗匹配(DCI)模块。芯片使用SMIC 1P10M65nm CMOS工艺流片。测试结果表明,芯片核心电路在1.2V电压下能保证各种协议工作正常,输入输出信号延时、最大输出电流、最高工作速率等与仿真结果吻合,均达到设计指标要求。     

基于FPGA的多信号合成的硬件设计与实现

提出了一种以FPGA为主控芯片、基于DDS技术的多信号合成设计方案,并用硬件实现了该系统。系统主要实现两个功能:首先,实现了输出8路频率、相位和幅度可调的正弦波信号;其次,将8路正弦波信号叠加后输出,完成了多路信号合成的硬件实现。硬件系统由数字逻辑部分和模拟电路两部分组成;数字逻辑部分在QuartusⅡ8.1上设计,并通过Active Serial Programming下载到FPGA的配置芯片EPCS4中,逻辑功能都在FPGA芯片内部完成;该部分控制液晶显示器和键盘,实现对正弦波信号的调制输出;模拟电路部分在Altium Designer Summer 09上设计,应用PCB工艺制作成电路板。模拟电路部分连接数字逻辑部分的输出,完成调制信号的滤波和信号合成。     

一种多接口电平输出频率综合器设计

针对目前不同芯片和设备之间接口电平标准不一样的问题,设计了一种多接口电平输出频率综合器。通过锁相环芯片产生1.6 GHz^3.2 GHz频段的信号,利用并行转串行芯片将锁相环产生的信号降频到FPGA能处理的频段,FPGA进行相应分频输出目标频率,最后通过电平转换电路调节信号的共差模电压实现目标电平输出。选择LVPECL、LVDS和+7 dBm 3种典型电平进行测试,测试结果表明,系统输出频率稳定,误差达到0.025%,转换电平的电压值误差最大为3.268 mV,满足系统设计要求。     

辐射加固SOI的SRAM基FPGA中IO模块阵列的设计与实现

本文中我们提出了一个用于辐射加固的SRAM基FPGA VS100的输入输出模块阵列,该FPGA用0.5微米部分耗尽SOI工艺设计,在中电集团58所流片。与FPGA的特性一致,每一个IO单元都由布线资源和两个IOC组成,IOC包括信号通路电路,可编程输入/输出驱动器和ESD保护网络组成。IO模块能用于不同的工作模式时,边界扫描电路既可以插入在输入输出数据路径电路和驱动器之间,也可以作为透明电路。可编程IO驱动器使IO模块能够用于TTL和CMOS电平标准。布线资源使得IO模块和内部逻辑之间的连接更加灵活和方便。辐射加固设计,包括A型体接触晶体管,H型体接触晶体管和特殊的D触发器的设计提高了抗辐射性能。ESD保护网络为端口上的高脉冲提供了放电路径,防止大电流损坏内部逻辑。这些设计方法可以适用于不同大小和结构的FPGA设计。IO单元阵列的功能和性能经过了功能测试和辐射测试的考验,辐照实验结果表明,抗总剂量水平超过100Krad(Si), 抗瞬态剂量率水平超过1.510¹¹rad(Si)/s,抗中子注入量水平达到110¹⁴ n/cm²。     

一种多接口电平输出频率综合器设计

针对目前不同芯片和设备之间接口电平标准不一样的问题,设计了一种多接口电平输出频率综合器,通过锁相环芯片产生1.6ＧＨｚ~ 3.2ＧＨｚ频段的信号,利用并行转串行芯片将锁相环产生的信号降频到FPGA能处理的频段,FPGA进行相应分频输出目标频率。最后通过电平转换电路调节信号的共差模电压实现目标电平输出,选择LVPECL、LVDS和+7ｄＢｍ3种典型电平进行测试,测试结果表明,系统输出频率稳定,误差达到0.025％,转换电平的电压值误差最大为3.268ｍＶ,满足系统设计要求。     

集成电路可测性设计IO复用方法

超大规模集成电路特征尺寸逐步缩小的发展过程中,芯片面积是制约芯片成本的最重要因素之一,也是直接影响半导体产品市场竞争力的最重要因素之一。本文介绍了将所有可测性设计(DFT)的输入输出端口(IO)与各种类型的正常功能工作模式的IO复用的方法,从而达到减少IO并最终减小芯片面积的目的。介绍了输入信号和输出信号分别在单向端口IO和双向端口IO中复用的方法。然后,以一款经过0.18μm逻辑工艺流片验证的flash存储器控制芯片为例,对比了采用IO复用方法前后芯片的利用率和面积,证明了方案的可行性和有效性。     

使用PIC16F877的PORTB端口电平变化中断实现键盘输入

<正> 在各种智能仪器和控制系统的设计中,我们常常需要用键盘来输入参数或对程序的进程进行管理,因此键盘是实现人机对话的一种重要输入方式。键盘分为编码键盘和非编码键盘两类。前者是由硬件电路实现键盘编码,由硬件来识别键闭合、键释放,消除键抖动影响以及实现一些保护措施的方法,可以节约CPU的时间,Intel公司推出的芯片8279就可以实现编码键盘。但是这种系统需要外加芯片,增加了系统的设计成本。非编码键盘电路简单,有的还可以直接利用单片机的I/O口进行扩展,键闭合、键释放以及消除键抖动都用软件来实现,成本较低,因此是一种广泛应用的键盘。非编码键盘键的识别可以采用查询方式或中断方式,后者具有更好的实时性。本文介绍利用PIC16F877单片机PORTB端口的电平变化中断来实现非编码键盘的方法。 1.PORTB端口“电平变化中断”简介 PIC16F877单片机PORTB端口的四个引脚RB7～RB4上有电平变化时可以产生中断,但只有当I/O引脚设置为输入状态时才能发生中断(RB7～RB4的任何一个引脚被配置为输出,则被排除在电平变化比较引起的中断以外)。其功能的实     

单片机硬件、软件及其应用讲座(14)——第八讲 输入/输出端口(上)

<正> 输入/输出端口(也可简称为I/O口)是单片机内部电路与外部世界交换信息的通道。输入端口负责从外界接收检测信号、键盘信号等各种开关量信号。输出端口负责向外界输送由内部电路产生的处理结果、显示信息、控制命令、驱动信号等。如果将单片机看作是一个为人服务的“奴仆”的话,那么单片机的I/O口也就是“主-仆对话”或称“人-机对话”的渠道。由此可见,输入/输出端口对于单片机来说是一种极其重要的外围模块,以至于对任何一个厂家生产的任何一种型号的单片机来说,输入/输出端口模块都是必不可少的。     

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.     

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.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Call for Papers

正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its