A Sub-1-V Low-Noise Bandgap Voltage Reference

A new sub-1-V bandgap voltage reference is presented in this paper, which has advantages over the prior arts in terms of output noise and compatibility with several fabrication processes. The topology allows the reference to operate with a supply voltage as low as 1 V by employing the reverse bandgap voltage principle (RBVP). It also has an attractive low-noise output without the use of a large external filtering capacitor. The design was fabricated with a 0.5-mum BiCMOS process, but it is compatible with most CMOS and BiCMOS fabrication processes. The entire die area is approximately 0.4 mm², including all test pads and dummy devices. Theoretical analysis and experimental results show that the output noise spectral density is 40 nV/radicHz with a bias current of 20 muA. Moreover, the peak-to-peak output noise in the 0.1-10 Hz band is only 4 muV. The untrimmed reference has a mean output voltage of 190.9 mV at room temperature, and it has a temperature coefficient in the -40degC to +125degC range of 11 ppm/degC (mean) with a standard deviation of 5 ppm/degC.     

A Compensated Bandgap Voltage Reference with Sub-1-V Supply Voltage

This paper describes a bandgap architecture with 0.35 and 0.55 V reference voltages that operates at a supply voltage below 0.8 V—the lowest yet reported for 0.6 um standard CMOS technology. The technique uses a well-known self-biased low-supply-voltage (PTAT) regulator and a novel current-controlled summing regulator. Both are combined into the new self-regulating current and voltage-mode architecture. The proposed architecture solves the problem of a wide operating-temperature range (−50 to 160°C).Two references have been processed: the first has vertical bipolar devices incorporated into a CMOS topology and the second is a pure CMOS solution. The temperature coefficient (TC), measured on 20 samples from one wafer, ranges from 7 to 20 ppm/°C and 20 to 38 ppm/°C respectively in the temperature range from −40 to 120°C, without trimming the TC.Good matching was found between the samples. The references consumed 2.5 uA each with a minimum supply of 0.8 V. The supply voltage could be lowered for a reduced temperature range.Anton Pleteršek was born in Maribor, Slovenia in 1952. He received the M.Sc. degree and the Ph.D. degree in electrical engineering from the University of Ljubljana, in 1982 and 1986. He works at the University of Ljubljana, FE, department on Microelectronic System Integration—LMFE, Ljubljana, Slovenia on mixed signal ASIC design. Since 1989 he is an Assistant professor at the Electronic Department of the Faculty of Electrical Engineering in Ljubljana.     

一种用于A/D转换器的低电压CMOS带隙电压基准源

设计了一种在1V电压下正常工作的用于A/D转换器的低功耗高精度的CMOS带隙电压基准.电路主要包括了一个带隙基准和一个运放电路,而且软启动电路不消耗静态电流.电路采用0.18μm CMOS工艺设计.仿真结果显示,温度从-40~125°C,温度系数约为1.93ppm/°C,同时电源抑制比在10kHz时为38.18dB.电源电压从0.9V到3.4V变化时,输出电压波动保持在0.17%以内;电路消耗总电流为5.18μA.     

Amorphous-Silicon Thin-Film Transistors Fabricated at 300 °C on a Free-Standing Foil Substrate of Clear Plastic

We have made hydrogenated amorphous-silicon thin-film transistors (TFTs) at a process temperature of 300^degC on free-standing clear-plastic foil substrates. The key to the achievement of flat and smooth samples was to design the mechanical stresses in the substrate passivation and transistor layers, allowing us to obtain functional transistors over the entire active surface. Back-channel-passivated TFTs made at 300 ^degC on glass substrates and plastic substrates have identical electrical characteristics and gate-bias-stress stability. These results suggest that free-standing clear-plastic foil can replace display glass as a substrate from the points of process temperature, substrate and device integrity, and TFT performance and stability.     

Compact 90° Releasable Multifiber Optical Connectivity Solution

A compact releasable 90deg optical connectivity solution is proposed, realized, and characterized. It can be used for angled interconnection between two small form factor multifiber connectors, or between one connector and surface mounted multichannel active optical elements such as vertical-cavity surface-emitting lasers and photodetector arrays. This 90deg connectivity system is based on V-groove substrates and an integrated optical microsystem combining two lens arrays and a 45deg mirror. Realized modules feature average fiber-to-fiber optical losses of 1.4 dB (best below 1 dB) for multimode operation over the whole wavelength range from 850 up to 1550 nm. This interconnect solution provides advantages when limited space is available (e.g., in optical distribution frames, splice closures, high-performance computers)     

一个1.2 V,9 ppm/℃的CMOS带隙电压基准源

基于传统CMOS带隙电压基准源电路的分析,结合曲率补偿技术设计了一种带衬底驱动运算放大器的低电源电压的电压基准源电路,主体电路采用电流模式基准源结构,并结合所采用的衬底驱动运放作为基准源的负反馈运放。整个电路采用0.5μm标准CMOS工艺实现,在电源电压1.2 V的条件下用HSpice进行仿真,仿真结果表明输出基准电压在-40~120℃范围内温度系数为9 ppm/℃。     

Amorphous Silicon Thin-Film Transistor Backplanes Deposited at 200 °C on Clear Plastic for Lamination to Electrophoretic Displays

The transition of thin-film transistor (TFT) backplanes from rigid plate glass to flexible substrates requires the development of a generic TFT backplane technology on a clear plastic substrate. To be sufficiently stable under bias stress, amorphous-silicon (a-Si:H) TFTs must be deposited at elevated temperatures, therefore the substrate must withstand high temperatures. We fabricated a-Si:H TFT backplanes on a clear plastic substrate at 200degC. The measured stability of the TFTs under gate bias stress was superior to TFTs fabricated at 150degC. The substrate was dimensionally stable within the measurement resolution of 1, allowing for well-aligned 8 times 8 and 32 times 32 arrays of pixels. The operation of the backplane is demonstrated with an electrophoretic display. This result is a step toward the drop-in replacement of glass substrates by plastic foil.     

A Full-360° Reflection-Type Phase Shifter With Constant Insertion Loss

A new reflection-type phase shifter with a full 360deg relative phase shift range and constant insertion loss is presented. This feature is obtained by incorporating a new cascaded connection of varactors into the impedance-transforming quadrature coupler. The required reactance variation of a varactor can be reduced by controlling the impedance ratio of the quadrature coupler. The implemented phase shifter achieves a measured maximal relative phase shift of 407deg, an averaged insertion loss of 4.4 dB and return losses better than 19 dB at 2 GHz. The insertion-loss variation is within plusmn0.1 and plusmn0.2 dB over the 360deg and 407deg relative phase shift tuning range, respectively.     

Cavity Mode—Gain Peak Tradeoff for 1320-nm Wafer-Fused VCSELs With 3-mW Single-Mode Emission Power and 10-Gb/s Modulation Speed Up to 70 °C

Room-temperature cavity mode red-shift of about 45nm from the photoluminescence peak is found to be optimal for tradeoff between high modulation bandwidth and good high-temperature performance for InAlGaAs(InP)-AlGaAs fused vertical-cavity surface-emitting lasers (VCSELs) employing tunnel junction carrier injection. Single-mode output power up to 5.4 and 3.1 mW, at 25 degC and 75 degC, respectively, and open eye diagrams exhibiting fall time values close to 40 ps at 10-Gb/s modulation up to at least 70 degC have been obtained for such VCSELs emitting at 1320-nm wavelength     

A Novel Miniature 1–22 GHz 90° MMIC Phase Shifter with Microstrip Radial Stubs

A novel miniature ultra wide bandwidth 90 monolithic microwave integrated circuit phase shifter with microstrip radial stubs operated from 1 to 22 GHz is presented. The phase shifter exhibits a high performance. Within the whole bandwidth from 1 to 22 GHz, the phase error of the phase shifter is less than 3deg, the return losses of the different phase shift states are more than 14 dB, the insertion loss of all phase shift states are within 3.3plusmn0.5 dB. The chip size of this phase shifter is 1.4 mm times 1.8 mm times 0.1 mm. The proposed phase shifter can be compatible with different polarity control signals without the need of drivers and can also be compatible with either analogue or digital control signals.     

90° Light Beam Deflection Technology for Single-Mode Optical Interconnection Systems

In this letter, we demonstrate an extremely low loss (<0.06 dB) 1-mm bending radius 90deg light deflection by using a 12-single-mode-fiber ribbon for optical interconnection systems. This technology is easy to be adopted for optical surface mount assemblies that need light beam deflection between the vertical surface-emitting lasers or surface-receiving photodiodes and optical paths parallel to an electric circuit board. We have chosen single-mode fiber (SMF) for the 90deg-bent fiber expecting the single-mode transmission will be applied for high-performance optical interconnection systems because of its wide bandwidth and stability in transmission characteristics. In order to minimize the bending loss and accomplish a small bending radius, we have developed a new optical fiber having higher refractive index of the core (high delta n fiber) than that of conventional fiber and 80-mum-cladding 125-mum spacing 12-fiber ribbon for dense packaging and easy handling in narrow spaces. It is bent at a radius of 1 mm by heating process with a ceramic heater.     

1V以下基于Vgs权重的CMOS恒压源

提出了一种新型CMOS恒压源的制作方案,它基于nMOS和pMOS的饱和区栅源电压随温度变化权重不同的原理,将两者做相关运算,得到零温度系数的恒压源.该电压源没有采用二极管和寄生三极管,并用SMIC 0.18μm数模混合工艺模型参数仿真并制造.测试结果表明,温度系数达到了44ppm/℃,PSRR为-46dB,650mV以上的电源电压就可以完全正常工作.芯片面积约为0.05mm2.     

A Wideband Bandpass Filter With Wide Upper Stopband Using Stepped-Impedance Cascadable 180 ° Hybrid Rings

This letter proposes a wideband bandpass filter by cascading two 3-dB stepped-impedance cascadable 180deg hybrid rings with a pair of stepped-impedance lines. Thanks to the stepped-impedance lines, a broad upper stopband is achieved. The stepped-impedance vertically installed planar (VIP) coupler is used to implement the ideal 180deg phase inverter and crossovers. The experimental results show that this 2-GHz center frequency, fourth order filter has a 10-dB return loss bandwidth of 92.5% and upper stopband rejection levels of better than -20 dB up to 6.8 GHz. This proposed filter achieves wide passband and broad stopband performance simultaneously.     

Mass Manufacturable 180 °-Bend Single-Mode Fiber Socket Using Hole-Assisted Low Bending Loss Fiber

High-efficiency low-cost field-installable 180deg-bend single-mode fiber (SMF) sockets are promising new fiber connector components that can facilitate network element footprint reduction and allow for more comfortable connector handling in the field. We present a novel type of small-form-factor 180deg coupling SMF socket component, yielding coupling losses between two side-by-side positioned fibers as low as 0.5 dB, making use of specially designed low bending loss hole-assisted fiber. The components are prototyped in a polymer using deep proton writing and show all the potentialities for low-cost fabrication in different types of plastics.     

一种10-ppm/~oC低压CMOS带隙电压基准源设计

在对传统CMOS带隙电压基准源电路分析和总结的基础上,综合一级温度补偿、电流反馈和电阻二次分压技术,提出了一种10-ppm/oC低压CMOS带隙电压基准源。采用差分放大器作为基准源的负反馈运放,简化了电路的设计,放大器的输出用于产生自身的电流源偏置,提高了电源抑制比(PSRR)。整个电路采用TSMC 0.35mm CMOS工艺实现,采用Hspice进行仿真,仿真结果证明了基准源具有低温度系数和高电源抑制比。     

一种10-ppm/℃低压CMOS带隙电压基准源设计

在对传统CMOS带隙电压基准源电路分析和总结的基础上，综合一级温度补偿、电流反馈和电阻二次分压技术，提出了一种10-ppm/℃低压CMOS带隙电压基准源。采用差分放大器作为基准源的负反馈运放，简化了电路的设计，放大器的输出用于产生自身的电流源偏置，提高了电源抑制比(PSRR)。整个电路采用TSMC 0.35μm CMOS工艺实现，采用Hspice进行仿真，仿真结果证明了基准源具有低温度系数和高电源抑制比。     

In-Fiber Twist Sensor Based on a Fiber Bragg Grating With 81° Tilted Structure

We report a strong polarization dependent coupling behavior of fiber Bragg gratings with excessively tilted structures up to 81deg. This unique property has been utilized to implement a novel twist sensor, showing high torsion sensitivity. The twist induced light coupling interchange between the two birefringence modes makes it possible to interrogate such a sensor using low-cost intensity demodulation technique     

Surface Reconstruction for Free-Space 360 ° Fluorescence Molecular Tomography and the Effects of Animal Motion

Complete projection (360deg) free-space fluorescence tomography of opaque media is poised to enable 3-D imaging through entire small animals in vivo with improved depth resolution compared to 360deg-projection fiber-based systems or limited-view angle systems. This approach can lead to a new generation of fluorescence molecular tomography (FMT) performance since it allows high spatial sampling of photon fields propagating through tissue at any projection, employing nonconstricted animal surfaces. Herein, we employ a volume carving method to capture 3-D surfaces of diffusive objects and register the captured surface in the geometry of an FMT 360deg-projection acquisition system to obtain 3-D fluorescence image reconstructions. Using experimental measurements we evaluate the accuracy of the surface capture procedure by reconstructing the surfaces of phantoms of known dimensions. We then employ this methodology to characterize the animal movement of anaesthetized animals. We find that the effects of animal movement on the FMT reconstructed image were within system resolution limits (~0.07 cm).     

A Nonisolated Single-Phase UPS Topology With 110-V/220-V Input–Output Voltage Ratings

A circuit configuration of a single-phase nonisolated online uninterruptible power supply (UPS) with 110-V/220-V input–output voltage ratings is proposed, allowing the bypass operation without a transformer even if the input voltage is different from the output voltage. The converter consists of an ac–dc/dc–dc three-level boost converter combined with a double half-bridge inverter. In this type of configuration size, cost and efficiency are improved due to the reduced number of switches and batteries, and also, no low-frequency isolation transformer is required to realize bypass operation because of the common neutral connection. Both stages of the proposed circuit operate at high frequency by using a passive nondissipative snubber circuit in the boost converter and insulated-gate bipolar-transistor switches in the double half-bridge inverter, with low conduction losses, low tail current, and low switching losses. Principle of operation and experimental results for a 2.6-kVA prototype are presented to demonstrate the UPS performance.      

一种用于模数转换器的高性能差分参考电压源

介绍了一种可直接应用于模数转换器的低功耗、高性能差分参考电压源.它采用新型结构的带隙基准源产生高精度温度补偿的参考电流,参考电流通过跨导缓冲器直接转换成所需的差分参考电压.该差分电压精度高、温漂小、抗干扰能力强.电路选用TSMC 0.18μm CMOS工艺实现,芯片面积为250μm×350μm.经测量,电路功耗为0.9mW,输出差分参考电压的平均温度系数为9.5×10-6K-1.