Performance of integrated dynamic MOS amplifiers

The letter presents measured data of two different types of dynamic amplifier which have been integrated in a standard CMOS metal gate technology. For a supply voltage of ±5 V, gains of 70 dB were obtained with a power dissipation of 58 ?W and 500 ?W at clock frequencies of 10 kHz and 100 kHz, respectively. The dynamic range exceeds 100 dB.     

Design of high-efficiency current-mode class-D amplifiers for wireless handsets

Design considerations are discussed for current-mode class-D (CMCD) microwave power amplifiers. Factors affecting amplifier efficiency are described analytically and via simulation. Amplifiers are reported that incorporate parallel LC resonators alongside the switching transistors. To reduce parasitic resistance, bond-wires were utilized to implement a high Q inductor in the LC resonator. An experimental CMCD amplifier based on GaAs HBTs is reported, with collector efficiency of 78.5% at an output power of 29.5 dBm (0.89 W) at 700 MHz.     

New techniques for drift compensation in integrated differential amplifiers

A technique is described for achieving low-voltage offset and thermal drift in a monolithic integrated differential amplifier. First order compensation is achieved, under severe restrictions, for a simple differential pair. An alternative balancing technique utilizes the linear combination of two equal and opposite drift characteristics to minimize drift from all sources. Drift values of /spl plusmn/0.12 /spl mu/V//spl deg/C over the temperature range 0 to 100/spl deg/C have been obtained.     

集成电流反馈运算放大器的应用与实践特性及应用设计

介绍电流反馈运算放大器包括电路组成，工作原理及有关的应用设计。     

Current divider: a new negative feedback element for integrated amplifiers

A multistage small-signal amplifier is described having, instead of resistors, a current divider in the negative-feedback pad. The current divider is a transistor which has two collectors with very different current gains. In spite of not using any passive components, linear and stable amplification has been achieved, down to input currents of 10?11 A.     

Performance comparison of GaInNAs vertical-cavity semiconductor optical amplifiers

This paper reports on theoretical and experimental investigations of the influence of the number of GaInNAs quantum wells (QWs) on performance of 1.3-/spl mu/m vertical-cavity semiconductor optical amplifiers (VCSOAs). Full characterization is carried out for two optically pumped VCSOAs with 6 and 15 QWs in the active layer. The 15-QW amplifier is found to be more efficient for amplification purposes but the highest gain to date was obtained for a 6-QW GaInNAs VCSOA, 19-dB on-chip gain in single-mode operation, having a top mirror reflectivity of 97.7%. At high-gain and for low enough reflectivity, the intrinsic noise figure is smaller than 5 dB.     

Erbium-doped fiber amplifiers with wavelength-selective optical feedback

An optically-controlled fiber ring laser behaving as a low-speed all-optical inverter was demonstrated. Applications in fault location for lightwave systems, nonlinear optical circuitry and simple logic functions are described. Two inverters using erbium-doped fiber amplifiers were cross-coupled to form an all-optical guided-wave set/reset hip-hop that had greater than 40-dB extinction ratio and a state transition time of 1.6 ms.     

Adaptive feedback techniques for synchronized multimedia retrievalover integrated networks

The authors have developed intermedia synchronization techniques for multimedia on-demand retrieval over integrated networks in the absence of global clocks. In these techniques, multimedia servers use lightweight messages called feedback units transmitted by media display sites (such as audiophones and videophones, generically referred to as mediaphones) to detect asynchronies among those sites. They present strategies by which the multimedia server can adaptively control the feedback transmission rate from that mediaphone, so as to minimize the associated overheads without permitting the asynchrony to exceed tolerable limits. They compare the performance of various resynchronization policies such as conservative, aggressive, and probabilistic. Performance evaluation of the feedback techniques indicates that their overheads are negligible; for a typical audio/video playback environment, the feedback frequency was about one in a hundred     

Silicon p-i-n photodetectors with integrated transistor amplifiers

A novel silicon photodetector is presented, incorporating transistor gain in a p-i-n photodiode and its performance is analyzed. Gain and noise power frequency characteristics are analytically derived in terms of an equivalent circuit. These analytical results are in good agreement with experimental results. Noise power is estimated and it is shown that, in the video frequency range, the S/N ratio is far superior to that of APD for relatively large signal levels. Detector operational features are described.     

Transconductance with capacitances feedback compensation for multistage amplifiers

A new performance-boosting frequency compensation technique is presented, named Transconductance with Capacitances Feedback Compensation (TCFC). A transconductance stage and two capacitors introduce negative feedback to a three-stage amplifier, which significantly improves the performance such as gain-bandwidth product, slew rate, stability and sensitivity. An optimized TCFC amplifier has been implemented, and fabricated in a 0.35-/spl mu/m CMOS process. The TCFC amplifier driving a 150-pF load capacitor achieved 2.9-MHz gain-bandwidth product dissipating only 45-/spl mu/W power with a 1.5 V supply, which shows a significant improvement in MHz/spl middot/pF/mA performance.     

Performance comparison of space-time coding techniques

Simulation results for the comparative performance of a number of space-time coding (STC) schemes in a multiple-input-multiple-output (MIMO) channel are presented and compared with a single-antenna benchmark and two-antenna space-time transit diversity (STTD) scheme. Both the space-time trellis coding (STTC) and BLAST approaches offer high spectral efficiencies, but STTC outperforms BLAST in terms of its power efficiency     

抗辐射加固版图技术的性能比较

Total ionizing dose （TID） effect and single event effect （SEE） from space may cause serious effects on bulk silicon and silicon on insulator （SOl） devices, so designers must pay much attention to these bad effects to achieve better performance. This paper presents different radiation-hardened layout techniques to mitigate TID and SEE effect on bulk silicon and SOl device and their corresponding advantages and disadvantages are studied in detail. Under 0.13μm bulk silicon and SOl process technology, performance comparisons of two different kinds of DFF circuit are made, of which one kind is only hardened in layout （protection ring for bulk silicon DFF, T-gate for SO! DFF）, while the other kind is also hardened in schematic such as DICE structure. The result shows that static power and leakage of SOI DFF is lower than that of bulk silicon DFF, while SOI DFF with T-gate is a little slower than bulk silicon DFF with protection ring, which will provide useful guidance for radiation-hardened circuit and layout design.     

Measurement applications of tuned feedback amplifiers

A feedback amplifier can be made to operate at a frequency determined by an included resonant circuit. Circuits can be constructed whose amplitude or frequency are extremely sensitive to changes to particular circuit parameters while being insensitive to all other parameter changes. Such behavior has broad application for various measurement and detection systems.     

A comparison of linear handset power amplifiers in different bipolar technologies

This work evaluates four linear power amplifiers for wireless handset applications that were fabricated (or simulated) in four different bipolar technologies. The four bipolar technologies are currently competing to become, or remain as, the preferred bipolar technology for the commercial development of power amplifier modules. The four technologies are GaAs HBT, Si BJT, SiGe HBT, and InP HBT. The purpose of this work is to evaluate the performance of power amplifiers in each of these competing technologies in terms of typical linear handset PA requirements (i.e., P/sub OUT/, ACPR, PAE, P/sub GAIN/, and ruggedness).     

Design of integrated BiCMOS operational amplifiers with low-probability EMI-induced-failures

Electromagnetic interference may cause failures in operational amplifiers. The probability of these failures can be reduced by properly designing the opamp, once the failure mechanism has been discovered. In this paper the design of some integrated BiCMOS operational amplifiers with a very low-probability of electromagnetic interference (EMI) induced failures is reported. In particular, it is shown that opamps exhibiting good general performances as well as low EMI-susceptibility can be obtained only if their response to a large square-wave input signal is symmetric and the influence of some parasitic capacitances in the input stage is compensated. Following these guide-lines, we found possible to design BiCMOS opamp structures exhibiting EMI susceptibility of only a few mV up to several hundred MHz when they are driven with an interfering input signal of some volts.     

Application of feedback techniques to the realisation of hybrid and monolithic broadband low-noise-and-power GaAs FET amplifiers

The implementation of ultrabroadband low-noise GaAs FET amplifiers operating up to 20 GHz is shown to be possible with the use of a low-parasitic high-gm device, which can only be implemented using monolithic circuit techniques. An example of a 0.1 to 6 GHz hybrid low-noise amplifier to illustrate the circuit technique is described.     

Applications of the current feedback operational amplifiers

The current feedback operational amplifiers (CFOAs) are receiving increasing attention as basic building blocks in analog circuit design. This paper gives an overview of the applications of the CFOAs, in particular several new circuits employing the CFOA as the active element are given. These circuits include differential voltage amplifiers, differential integrators, nonideal and ideal inductors, frequency dependent negative resistors and filters. The advantages of using the CFOAs in realizing low sensitivity universal filters with grounded elements will be demonstrated by several new circuits suitable for VLSI implementation. PSPICE simulations using the AD844-CFOA which indicate the frequency limitations of some of the proposed circuits are included.     

Macromodeling of integrated circuit operational amplifiers

A macromodel has been developed for integrated circuit (IC) op amps which provides an excellent pin-for-pin representation. The model elements are those which are common to most circuit simulators. The macromodel is a factor of more than six times less complex than the original circuit, and provides simulated circuit responses that have run times which are an order of magnitude faster and less costly in comparison to modeling the op amp at the electronic device level. Expressions for the values of the elements of the macromodel are developed starting from values of typical response characteristics of the op amp. Examples are given for three representative op amps. In addition, the performance of the macromodel in linear and nonlinear systems is presented. For comparison, the simulated circuit performance when modeling at the device level is also demonstrated.     

A floating generalized impedance converter with current feedback operational amplifiers

A novel generalized impedance converter topology realized using current feedback operational amplifiers is introduced in this paper. The main offered benefit, in comparison to the corresponding already published structure, is that frequency dependent negative resistors can now be also realized. Other benefits are the requirement for only grounded capacitors, the lower component count, and the capability of tuning through a grounded resistor. The correct operation of the proposed GIC has been verified through a design example, where a 3rd-order lowpass filter has been topologically simulated.     

Design of sampled grating DBR lasers with integrated semiconductoroptical amplifiers

High output powers and wide range quasicontinuous tuning have been achieved in a sampled-grating distributed Bragg reflector laser with an integrated semiconductor-optical-amplifier. Using an amplifier with a curved passive output waveguide to suppress back reflection, we have achieved a quasicontinuous tuning range of over 50 nm and peak output powers greater than +8 dBm. Optimizing the device structure and the sampled-grating mirror design has enabled tuning ranges of up to 72 nm in devices without amplifiers