温度补偿的30nA CMOS电流源及在LDO中的应用

设计了一种新型的用于低功耗LDO线性稳压器的CMOS高精度参考电流源.通过亚阈值设计方法得到30nA与电源电压无关的基准电流.利用MOS管寄生二极管反向电流的高温特性,对各支路的镜像电流进行了温度补偿,在-40～130℃范围内的30nA的基准电流精度从±1.5nA提高到±0.9nA.用这种参考电流源设计的LDO的静态电流在-40～130℃范围时减小到4μA.用Cadence公司的Spectre软件以及CSMC的0.5μm CMOS混合信号模型对电路进行了仿真与芯片设计.芯片测试结果验证了以上设计.     

恒流LDO型串联大功率白光LED驱动器的设计

介绍了一种LDO型串联大功率白光LED恒流驱动控制器的设计.该电路包括LDO、带隙基准电压源、反馈电路、电流传感取样电路、大功率驱动电路五个部分.芯片采用9 V供电,利用片内集成的LDO电路输出5 V电压,作为控制部分的电源电压.采用台积电0.35μm 2P4M N阱CMOS标准工艺完成设计.Spectre仿真结果表明,当电源电压在±10%之间跳变或环境温度在0℃～100℃之间变化时,芯片可为3 W白光LED提供350 mA恒定驱动电流,误差小于±0.5%,电源利用效率可达76.17%以上.     

一种低功耗低温度系数基准电压源的设计

基于0.35μm CMOS工艺,设计一种不带电阻的低功耗基准电压源,该基准源工作电压范围1.2 V~3.6 V.在3.6 V和室温时测量最大的电源电流为130 nA.在-20℃~100℃温度范围内,该基准电压温度系数为7.5×10-6/℃.在1.2 V~3.6 V电源电压范围内,线灵敏度为40×10-6/V,且在100 Hz时电源抑制比为-50 dB.该基准电压源适合在一些例如移动设备、植入式医疗设备和智能传感器网络等节能集成电路上应用.     

应用于WSN射频前端带隙基准设计

本文给出一种应用于无线传感网（Wireless Sensor Network,WSN）射频前端芯片低压差稳压器（Low Dropout Regulator,LDO）模块,采用SMIC0.18μm MM/RF CMOS工艺的低功耗、高电源抑制比、低温度系数的带隙基准电压源的设计。带隙基准电压源采用输出电压可调结构和高阶温度补偿技术,在Cadence Spectre仿真环境下的仿真结果表明它满足射频前端的系统要求,静态工作电流约为30μA,电源抑制比可达到-72dB,在-40℃至85℃范围内温度系数约为6×10^-6/℃。     

0.6V电源电压的CMOS基准源设计及稳定性分析

在SMIC 0.18μm CMOS工艺下实现了一种工作在0.6～1.5V下的基准源.分别采用环路增益法和返回比法对其中的自偏置放大器和核心电路的环路特性进行了分析.芯片输出的基准电压为0.4V,工作电流为4.8μA,在-40～120℃范围内温度系数小于80ppm/℃,面积(不包括PAD)为0.045mm2.     

0.6V电源电压的CMOS基准源设计及稳定性分析

在SMIC 0.18μm CMOS工艺下实现了一种工作在0.6～1.5V下的基准源.分别采用环路增益法和返回比法对其中的自偏置放大器和核心电路的环路特性进行了分析.芯片输出的基准电压为0.4V,工作电流为4.8μA,在-40～120℃范围内温度系数小于80ppm/℃,面积(不包括PAD)为0.045mm2.     

一种低功耗曲率补偿带隙基准电压源

设计了一种低功耗曲率补偿带隙基准电压源。利用亚阈值MOS管差分对,产生曲率补偿电流,对输出基准电压进行曲率补偿。采用低功耗运放来增强基准电压源的电源抑制能力,同时降低基准电压源的功耗。采用SMIC 0.18 μm 混合信号CMOS工艺进行设计。仿真结果表明,在1.5 V电源电压下,基准电压源的输出基准电压为1.224 V,在-40 ℃~125 ℃范围内的温度系数为1.440×10-6/℃~4.076×10-6/℃,电源抑制比为-77.58 dB,消耗电流为225.54 nA。     

低功耗微型电源管理IC的基准源设计

针对智能手机功能集成度与功耗的矛盾,提出了一种适用于射频和基带的微型电源管理IC新架构,并基于MOS器件的亚阈值特性,详细地给出其中具有低功耗零温漂的电流基准及电压基准电路的设计。基于TSMC 0.25μm CMOS混合信号工艺,通过Cadence公司的Spectre软件进行仿真验证。结果表明,在-20℃~110℃范围温度内,基准源在工作电压为3.6 V时,可输出50 nA±0.25 nA的基准电流;当电源电压在0.8~4 V变化时,可提供稳定的0.671 V基准电压,其中在0℃~50℃的常温内,具有1.49×10-5/℃的温度系数;在0~100 kHz频率范围内,基准源的PSRR可达到-74 dB。     

低温漂高PSRR新型带隙基准电压源的研制

利用带隙电压基准的基本原理,结合自偏置共源共栅电流镜以及适当的启动电路,设计了一种新型基准电压源。获得了一个低温度系数、高电源抑制比的电压基准。通过对输出端添加运算放大器,把带隙基准电路产生的1.2 V电压提高到3.5 V,提高了芯片性能。用Cadence软件和CSMC的0.5μm CMOS工艺进行了仿真,结果表明,当温度在-20～+120℃,温度系数为9.3×10-6/℃,直流时的电源抑制比为-82 dB。该基准电压源能够满足开关电源管理芯片的使用要求,并取得了较好的效果。     

一种高性能CMOS基准电流源的设计

采用温度补偿技术设计了一种高性能的CMOS基准电流源电路,该电路采用N阱CMOS工艺实现.通过Cadence Spectres仿真和测试的结果表明,在-40～85℃的温度范围内,该电路输出基准电流的温度系数小于40ppm/℃,基准电流对电源电压的灵敏度小于0.1％.在3.3V电源电压下功耗仅为1.3mW,属于低温漂、低功耗的基准电流源.     

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.     

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.     

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.     

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.     

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     

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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