新型低压差、负压线性稳压器MAX1735

MAX1735是MAXIM公司2000年7月份推出的新产品,是一种低压差、负电压输出线性稳压器。该器件主要特点有:保证输出200mA电流;在200mA输出时典型压差值为80mV;静态电流小,典型值为85μA;有关闭控制,在关闭模式时耗电仅1nA(典型值);输出电容仅需1μF;有过热保护及短路保护;它既能输出固定电压-5V、-3.0V、-2.5V,也能输出-1.25～-5.5V可调整电压;小尺寸SOT23-5封装。     

小尺寸封装的线性稳压系列

本文介绍一种型号为MIC5213的线性稳压器系列。该系列主要特点有:采用超小型SC-70封装,其面积只有SOT-23的一半,一个SO-8封装的面积中可放入7只SC-70封装的IC,具体尺寸为2mm×2.1mm×1mm(长×宽×高)。这是目前尺寸较小的线性稳压电源;该系列有四种固定输出:2.8V、3.0V、3.3V及3.6V;输出电流可达80mA;80mA输出时压差典型值为300mV;输出电压精度±3％,输出电压温度系数典型值为50ppm/℃;地电流在20mA输出时典型值为225μA;有     

一种两级误差放大器结构的LDO设计

基于SMIC 0.18μm CMOS工艺,设计了一种两级误差放大器结构的LDO稳压器。该电路运用两级误差放大器串联方式来改善LDO的瞬态响应性能,采用米勒频率补偿方式提高其稳定性。两级放大器中主放大器运用标准的折叠式共源共栅放大器,决定了电路的主要性能参数;第二级使用带有AB类输出的快速放大器,用来监控LDO输出电压的变化,以快速地响应此变化。电路仿真结果显示:在电源电压为5 V时,输出为1.8 V,输出电压的温度系数为10×10-6/℃;当电源电压从4.5 V到5.5 V变化时,线性瞬态跳变为48 mV;当负载电流从0 mA到60 mA变化时,负载瞬态跳变为5 mV。且环路的相位裕度为74°,整个电路的静态电流为37μA。该电路结构的瞬态跳变电压值远小于其他电路结构,且能实现低功耗供电。     

40V_(IN)、2.1A轨至轨LDO+可提供广泛的监视、保护和电缆压降补偿

<正>2013年12月18日,凌力尔特公司(Linear Technology Corporation)推出LDO+TM系列的最新器件LT3086,该器件提供了以前线性稳压器所没有的重要功能。该40 V、2.1 A低压差线性稳压器(LDO)具有电流监视(利用可在外部设定的电流限值)和温度监视(采用外部控制的热限制温度)功能。LT3086包括一个可编程电源良好状态标记,提供电缆压降补偿,且易于并联。LT308x LDO系列器件的电流基准可提供不受输出电压影响的调节。LT3086具备1.4 V~40 V的输入电压范围。单个电阻器在0.4 V~32 V范围内设定输出电压,压差电压在2.1 A时仅为     

双输出正/负±20V_(IN)、±150mA LDO的噪声仅为20μV_(RMS)

<正>2010年2月26日,凌力尔特公司(Linear Technology Corporation)推出双输出、低噪声、正/负低压差电压线性稳压器LT3032。在满负载时,该器件以300mV压差电压在每个通道上提供高达±150mA的连续输出电流。     

Maxim推出微型1A/500 mA LDO稳压器

<正>Maxim推出低压差(LDO)线性稳压器MAX15027-MAX15030,这些稳压器工作于1.425 V～3.6 V输入电压,能够提供高达1 A(MAX15027/MAX15028)或500 mA(MAX15029/MAX15030)的输出电流。另外,MAX15028/     

一种基于CLASS-AB类运放的无片外电容LDO设计

介绍了一种基于CLASS-AB类运放无片外电容的低压差线性稳压器（LDO）。电路在高摆率误差放大器（EA）的基础上,通过构建动态偏置电路反馈到EA内部动态偏置管,大幅改善了LDO的瞬态响应能力,且动态偏置电路引入的左半平面零点保证了LDO的环路稳定性。同时,EA采用过冲检测电路减小了输出过冲,缩短了环路稳定时间。电路基于65 nm CMOS工艺设计和仿真。仿真结果表明,在负载电流10μA～50 mA、输出电容0～50 pF条件下,LDO输出稳定无振荡。在LDO输入2.5 V、输出1.2 V、无片外电容条件下,控制负载在10μA和50 mA间跳变,LDO输出恢复时间为0.7μs和0.8μs,下冲和上冲电压为58 mV和15 mV。     

低压差、低功耗、高精度的电压调节器TC47系列

TC47系列是美国Telcom公司的产品,是一种电压调节器IC,外接一个PNP晶体管可组成稳压器。该系列组成的稳压器有如下的特点:输出电压精度(±2.5％);消耗电流小(50μA);有“等待”状态控制,其静态电流仅为0.2μA;压差低(在100mA输出时,其典型值为0.1V);线性调整率高(0.1％/V);输出电压分档极细(0.1V为一档),输出电压范围宽(2.0～6.0V)。     

一种高稳定性、快速瞬态响应低压差LDO

基于上华0.5 μm工艺设计了用于DC/DC的CMOS低压差线性稳压器,其输入电压为3.3 V,输出电压为1.2V,最大输出电流为100 mA;提出了一种补偿网络,保证负载电流发生变化时,LDO具有高稳定性.此外,还设计了一种瞬态响应改善电路来提高负载瞬态响应.仿真结果表明,该LDO在不同负载情况下的相位裕度均为80°,流片测试结果显示瞬态响应良好.     

超低噪声、高PSRR、低压差线性稳压器

<正>Maxim推出业界最小的、500mA、低噪声、低压差(LDO)线性稳压器MAX8902A/MAX8902B。该系列器件采用微型、2mm×2mm TDFN封装,可提供92dB PSRR (5kHz时)、16μV_(RMS)输出噪声以及满负载(500mA)时低达100mV(最大)的压差。MAX8902A/MAX8902B对于噪声敏     

低功耗、低成本、高可靠性、低复杂度的无线电通信协议--ZigBee

作为无线个人网中低数据传输率协议IEEE802．15．4／ZigBee，以低功耗、高可靠性、低复杂度见长。本文从在ISO通信模型的各通信层中所采用的协议进行分析，指出选择适当的经过实际验证的协议，并充分考虑各层协议的优化组合，是它取得高可靠性和低功耗的保证。     

低相位噪声低功耗LC压控振荡器的设计

在分析压控振荡器相位噪声的基础上,通过采用尾电流整形滤波技术设计了一种低相位噪声低功耗差分LC压控振荡器.电路设计采用TSMC 0.18um 1P6M CMOS RF工艺,利用Cadence软件中的SpectreRF工具对电路进行了仿真,结果显示,在电源电压VDD=1.8V时,其中心频率为1.8GHz,频率的变化范围为1.43～1.82 GHz,相位噪声为-121dBc/Hz@600kHz.静态功耗仅为2.5mW(1.8V×1.39mA).     

双面激打 低碳办公

随着打印机市场的不断发展,各类企业甚至家庭都配有打印机,据调查,在企业日常办公中,黑白文件的打印占主要部分,企业中一般都会有一台墨白激光打印机,用来文件打印,再有一台彩打来满足彩打需要。黑白激光打印机负担主要工作量,那么在当前低碳环保理念的大环境下,高效节能显     

Low Angle Estimation: Models,Methods, and Bounds

Boman, K. and Stoica, P., Low Angle Estimation: Models, Methods, and Bounds. Digital Signal Processing11 (2001), 35–79.In this work we study the performance of elevation estimators and lower bounds of the estimation error variance for a low angle target in a smooth sea scenario using an antenna array. The article is structured around some key assumptions on multipath knowledge, signal parameterization and noise covariance. We prove that the Cramér–Rao bound is highly dependent on the multipath model, while it is the same for the different signal parameterizations, and that it is independent of the noise covariance. The Cramér–Rao bound is sometimes too optimistic and not achievable. The tighter Barankin bound is derived to predict the threshold behavior seen at low SNR. Simulations show that the maximum likelihood methods are statistically efficient and achieve the theoretical lower bound on error variance, in the case of high enough SNR. Finally we show that the bounds can be used to design an improved array structure and study the influence of multiple frequencies.     

反思城市规划 建设低碳城市

<正>低碳发展以低能耗、低物耗、低排放、低污染为特征,建设生态城市,是人类理念的新发展。一、交通拥塞反思规划近年来,北京等大城市的交通拥堵日益严重;有些中小城市也出现交通阻塞;一些小城镇,自行车通达效果良好,而小汽车热使排放急剧增加。类似情况国外也有,1933年他们制定"雅典宪章",1977年制定"马丘比丘宪章"。前者的主导思想是把城市     

IKAROS: An HTTP-Based Distributed File System, for Low Consumption & Low Specification Devices

We present the design of IKAROS: an HTTP-based distributed file system, which provides file access scalability and targets a large variety of operating systems and storage systems. IKAROS bypasses the server bottleneck enabling clients to access storage directly, while supporting the usage of multiple types of meta-data. It enables low-consumption, low-specification and low-cost devices to achieve a high throughput data transfer, responding to highly demanding applications. We present data transfer results comparing IKAROS, NFS, PVFS2 and HDFS on a Small Office/Home Office Network Attached Storage infrastructure. We show that IKAROS architecture satisfies and outperforms the data rate demands of high performance applications. We also present experimental results which compare IKAROS and GridFTP using the European Grid Infrastructure. IKAROS performs better in most cases while being competitive at the rest.     

The Biodynamic Aspects of Low Altitude,High Speed Flight

Abstract

The physical forces encountered by an aircraft in low altitude, high speed flight can be particularly stressful to the aviator. The gross physical elements which make up this envelope are the dynamic profile of the aircraft, the flight pattern, and the dynamic profile of the atmospheric environment. The specific dynamic factors, whose application results in a physiological response in the pilot, are vibration, buffeting, angular acceleration, and gross acceleration of operator origin. The physiological systems of the aviator that are primarily responsive to the overall dynamic stresses are the cardiovascular, respiratory, neurohormonal, labyrinthine, visual and skeletal systems. The physiological variations observed in pilots in actual low altitude, high speed flight both in-flight and po3t-flight suggest the application of the general adaptation syndrome. Comparative results from in-flight observations and simulator studies demonstrate differences in physiological recordings which suggest the absence of apprehension as being a major defect in simulation as an indicator of pilot performance in low altitude, high speed flight. Protective systems for the pilot in the low altitude, high speed flight profile are those of good restraints, antibuffeting helmets, possible use of positioning and the use of an aeroplane which is ‘ least demanding ’ of the pilot. The need for more experimentation both in flight and in suitable simulators is apparent.     

Low Z substrates for cost effective high-energy, stacked exposures

 Commercial application of the “direct” LIGA process requires solving two critical issues: throughput and price. Stacking of PMMA sheets bonded to substrates and exposed simultaneously with hard X-ray has been suggested recently. This paper presents a comparison of potential low Z substrates for stacked exposures in deep X-ray lithography based on elements of the second row of the periodic table. The transmission of various substrates considered for such an application have been calculated and experimentally determined. The transmission properties of materias such a beryllium, carbon, boron and compounds are by far better than that of silicon at lower photon energies typically used in LIGA applications, but this gain decreases with increasing photon energy. In stacked exposures, however, even small gains provide significant decrease in exposure time. Received: 25 August 1997/Accepted: 3 September 1997