Amplifier Design Research Articles

Design and Analysis of Miller Compensated Two-Stage Operational Amplifier

Abstract. With the development of integrated circuit technology, the size of electronic equipment continues to reduce, and speed continues to increase. Operational amplifiers are the key circuit in analog ICs, and the required performance of operational amplifiers is also increasingly high, research and design of high-performance operational amplifiers has become one of the key topics of today's research. A CMOS two-stage operational amplifier with high unity-gain bandwidth is analysed and designed with an appropriate Miller-compensation technique in this research to improve the frequency characteristics and stability. The design is based on 180nm CMOS process. Its performance is simulated and analysed in Cadence software environment. The performance parameters are shown by simulation results that the amplifier has a gain of 61.81dB, a GB (unity-gain bandwidth) of 907.42MHz and a phase margin of 75.02. The experimental results show that it achieves high unity-gain bandwidth while ensuring gain and stability. Through this study, the principles of two-stage operational amplifiers and their compensation as well as the design and simulation are shown in detail in both theoretical and experimental sections.

Design of multi-octave power amplifier based on feedback structure of butterworth filter

Design of multi-octave power amplifier based on feedback structure of butterworth filter

Ultra Wideband High-Efficiency High-Power Amplifier Design by Simplified Output Matching Technique

Ultra Wideband High-Efficiency High-Power Amplifier Design by Simplified Output Matching Technique

Research and optimization of the gain characteristics of cascode amplifiers

Abstract. With the continuous development of IC technology, high-performance operational amplifiers are widely used in various circuit systems such as high-speed Analog-to-Digital Converters (ADCs), Digital-to-Analog Converters (DACs), switched capacitor filters, bandgap voltage reference sources, precision comparators. The amplifier has become the core unit circuit of analog IC and mixed-signal IC design, and its performance directly affects the overall performance of the circuit and system. The design of high-performance operational amplifiers has always been one of the hotspots in the research of analog IC design in order to meet the needs of various application fields. Cascode Amplifier is a classic structure widely used in high-frequency and high-gain electronic circuits. This project aims to study the gain characteristics of cascode amplifiers, explore the main factors affecting their gain, and propose methods to optimize the gain. Through theoretical analysis and simulation, the influence of different parameters on gain is verified. Then the optimization strategy is summarized to provide a reference for actual circuit design.

Design and optimisation of a two-stage amplifier based on a differential input stage and a common-source amplifier

Abstract. Since the emergence of integrated circuits, through the circuit structure, the production process of continuous iterative updating, so that its used in various types of electronic equipment more and more widely. Currently, operational amplifier circuits play an extremely important role in signal processing and communication systems. Amplifiers have different characteristics depending on the needs of different electronic devices. This thesis addresses the optimisation and design of the characteristics of the two-stages amplifier. Firstly, several classical amplifier structures are analysed. Select the appropriate structure and combine it into a two-stages amplifier. Simulation is carried out on cadence software and later the simulation results are analysed before parameter optimisation. On this basis, a two-stages amplifier based on a PMOS differential input stage with a common-source amplifier has been designed. It also improves the amplifier's gain, frequency range, gain bandwidth, and other performance metrics. Using PMOS self-bias circuit to improve power supply stability. Finally, based on the development hotspots of integrated circuits, the possibility of circuit optimization was analyzed. Discussions were conducted on negative feedback circuits, phase compensation methods, and other aspects.

Analysis of Gain Enhancement Techniques in Integrated Circuit Design

Abstract. Today, the size of semiconductor devices is still decreasing, which makes the circuit more integrated, faster computing speed, and lower power consumption. But for a single transistor, some performance degrades. One of the important properties is voltage gain, which must be compensated with some special methods in the design. This paper will focus on the discussion and analysis of four methods, which are able to improve the voltage gain. These are cascode amplifier, cascade amplifier, gain boosting, and bootstrapping. In this letter, their respective advantages and disadvantages will be discussed. Furthermore current applications and possible external development of these methods are also important part of this paper. In this part, the discussion will be further expanded and summarized on the basis of previous studies. Hopefully, these studies can help others gain a more comprehensive understanding of these technologies and provide a theoretical basis for future high-performance analog integrated operational amplifier research and design.

A Study of Techniques to Increase Amplifier Gain

Abstract. Improving amplifier gain has been one of the key topics in electronics. Although many techniques or structures have been created to increase amplifier gain, the increase in gain largely leads to changes in other parameters such as stability and bandwidth. Therefore, the aim of this paper is to investigate basic common-source amplifiers, common-source common-gate structures and current cancellation techniques, a total of five basic circuit structures for increasing amplifier gain, and to compare and analyse them based on some of their parameters. This paper uses a combination of theoretical derivation and simulation and experimental verification to carry out the study. Finally, the advantages and disadvantages of each structure as well as the application scenarios and development prospects are listed. Through this paper, researchers can not only have a basic understanding of the above structures, but also have a more intuitive understanding of the design of amplifiers as a multi-dimensional optimisation problem. It is essential to design the right amplifier for different circuit requirements.

Josephson traveling wave parametric amplifiers with plasma oscillation phase matching

High gain and large bandwidth of traveling-wave parametric amplifier exploiting the nonlinearity of Josephson Junctions can be achieved by fulfilling the so-called phase-matching condition. This condition is usually addressed by placing resonant structures along the waveguide or by periodic modulations of its parameters, creating gaps in the waveguide’s dispersion. Here, we propose to employ the Josephson junctions, which constitute the centerline of the amplifier, as resonant elements for phase matching. By numerical simulations in JoSIM (and WRspice) software, we show that Josephson plasma oscillations can be utilized to create wave vector mismatch sufficient for phase matching as well as to prevent the conversion of the pump energy to higher harmonics. The proposed traveling wave parametric amplifier design has a gain of 15 dB and a 3 GHz bandwidth, which is comparable to the state-of-the-art TWPAs.

Thermal design of a solid-state power amplifier at Q-band

Abstract It is very difficult to cool a new solid-state power amplifier at Q-band, which is composed of some high-power monolithic millimeter-wave integrated circuit chips. Cu/Diamond carriers are used as the heat sinks of the chips, and two layers of heat pipes are sealed in the chassis to reduce the thermal resistance of the amplifier. The thermal design scheme is proved useful by simulating Flotherm and the temperature data from the infrared imager. The study provides an available way for the thermal design of a solid-state power amplifier.

An active two-stage class-J power amplifier design for smart grid’s 5G wireless networks

<span>The wireless communication networks in the smart grid’s advanced metering infrastructure (AMI) applications need 5G technology to support large data transmission efficiently. As the 5G wireless communication network’s overall bandwidth (BW) and efficiency depend on its power amplifier (PA), in this work, a two-stage class-J power amplifier’s design methodology that operates at 3.5 GHz centre frequency by utilizing the CGH40010F model gallium nitride (GaN) transistor is presented. The proposed design methodology involves proper designing of input, output, and interstage matching networks to achieve class-J operation with improved power gain over desired BW using the advanced design system (ADS) electronic design automation (EDA) tool and estimating its integration feasibility through active element-based design approach using the Mentor Graphics EDA tool. The proposed PA provides 54% drain efficiency (D.E), 53% power added efficiency (PAE) with a small signal gain of 27 dB at 3.5 GHz and 41 dBm power output with 21 dB of improved power gain across a BW of around 400 MHz using 28 V power supply into 50 Ω load. By replacing the two-stage PA's passive elements with active elements, its layout size is estimated to be (15.5×29.2) μm2 . The results of the proposed PA exhibit its integration feasibility and suitability for the smart grid’s 5G wireless networks.</span>

Optimization Analysis of Low-Noise Amplifier

This paper mainly analyzes the important component of a wireless receiver – low-noise amplifiers (LNA). Low-noise amplifiers can reduce the effect of noise on the received signal and amplify signals. For the better development of wireless communication technology, remote control, and other related fields, it is necessary to optimize the design of low-noise amplifiers, so that low-noise operational amplifiers can finally obtain high gain, low noise figure, and other advantages. This paper analyzes the optimization design of LNA in the field of Global Navigation Satellite Systems (GNSS). This paper analyzes a low-noise amplifier design with the operation of concurrent dual-band for GNSS receivers with a single channel. The optimized design of a low-noise amplifier in this field uses a low-cost 0.18µm CMOS tube and adds load capacitances and a feedforward path to reduce the noise figure (NF) of the system. Noise figures in 1.2 GHz and 1.57 GHz bands are reduced by about 0.9 dB. In addition, the high gain, high linearity, and other excellent properties are shown in 1.2 GHz and 1.57GHz. In the application of 5G/6G network technology, the optimized design of Gallium Arsenide (GaAs) PHEMT technology with a gate length of 0.3µmm and inductively degraded common source topology phase structure is adopted. From this optimization, the noise figure is optimized to 1.3-1.4, and the gain of the system is 20-22 dB. At the same time, good linearity is also shown. Then, the prospects of semiconductor materials such as Gallium Nitride (GaN) and Indium Phosphide (InP), which have the advantages of high electron mobility and low-cost design, in optimizing low noise operational amplifiers. To a certain extent, the in-depth study of the optimal design of LNA can improve the technical level of wireless communication, aerospace, and other fields.

A high-sensitivity flexible bionic tentacle sensor for multidimensional force sensing and autonomous obstacle avoidance applications

Bionic tentacle sensors are important in various fields, including obstacle avoidance, human‒machine interfaces, and soft robotics. However, most traditional tentacle sensors are based on rigid substrates, resulting in difficulty in detecting multidirectional forces originating from the external environment, which limits their application in complex environments. Herein, we proposed a high-sensitivity flexible bionic tentacle sensors (FBTSs). Specifically, the FBTS featured an ultrahigh sensitivity of 37.6 N−1 and an ultralow detection limit of 2.4 mN, which benefited from the design of a whisker-like signal amplifier and crossbeam architecture. Moreover, the FBTS exhibited favorable linearity (R2 = 0.98) and remarkable durability (more than 5000 cycles). This was determined according to the improvement in the uniformity of the sensing layer through a high-shear dispersion process. In addition, the FBTS could accurately distinguish the direction of external stimuli, resulting in the FBTS achieving roughness recognition, wind speed detection and autonomous obstacle avoidance. In particular, the ability of autonomous obstacle avoidance was suitably demonstrated by leading a bionic rat through a maze with the FBTS. Notably, the proposed FBTS could be widely applied in tactile sensing, orientation perception, and obstacle avoidance.

Smith Chart-Based Design of High-Frequency Broadband Power Amplifiers

This paper presents a comprehensive study on the design and performance of a high-power amplifier (PA) covering a broad frequency band from 0.1 to 4.8 GHz. Leveraging a 10 W GaN device, the amplifier achieves output power levels surpassing 10 W across the entire frequency band. Furthermore, the power-added efficiency (PAE) of the amplifier ranges from 47% to 59%, indicating its energy-efficient operation. With consistent gain characteristics varying between 7 and 15 dB, the design ensures reliable signal amplification for diverse applications. Notably, the approach introduces a simplified output matching network based on an LC network, prioritizing practicality without sacrificing performance. Additionally, comprehensive guidance is provided on utilizing the Smith chart for streamlined amplifier design, enabling engineers with an accessible methodology. Through a meticulous analysis, this work contributes to advancing the field of high-power amplification, offering enhanced performance and usability for next-generation wireless communication systems.

Design of an ultra-wideband high-efficiency power amplifier based on multi-paths impedance matching structure

Design of an ultra-wideband high-efficiency power amplifier based on multi-paths impedance matching structure

Doherty Power Amplifier Design via Differential Combining

This paper introduces a novel differential combiner designed to effectively address parasitic capacitances of transistors used in power amplifier (PA) designs with precise compensation at a specified frequency. The combiner consists of a λ/4 transmission line with an integrated capacitor of value 2COUT at its midpoint, which ensures accurate cancellation of parasitic effects. This design connects the drain pins of two transistors, which are considered identical in this configuration. By eliminating the need for complex parasitic compensation techniques, this method significantly simplifies the design process of Doherty Power Amplifiers (DPAs). Extensive simulations validate the effectiveness of this approach, highlighting its potential as a versatile and straightforward solution for next-generation communication systems.

Astigmatic thermal lensing due to surface bulging in Yb:KYW laser crystals

One of the sources of thermal lensing in crystals is surface bulging that results from an inhomogeneous temperature distribution. We investigate a thermal lens caused by surface bulging in an end-pumped Yb:KYW crystal, which serves as a gain medium in lasers and optical amplifiers. The surface profile of the pumped crystal is measured using a Fizeau-type interferometer and compared with a numerical simulation using a finite element method. The study reveals that due to anisotropic thermal expansion, the surface shape of the Yb:KYW crystal is anisotropic and the profile of the expansion is transversely displaced with respect to the pump beam profile which generates the temperature distribution. The observed surface bulging gives rise to aberrations and deflection of the transmitted beam. It was found that the surface bulging introduces astigmatism that is significantly larger than previously estimated [Appl. Opt. 56, 3857 (2017)10.1364/AO.56.003857]. Our results allow the evaluation of the bulging contribution with improved accuracy. We show that these effects can be significant in certain designs of amplifiers and lasers.

Design and analysis of a piezo-actuated hydraulic micro-displacement amplifier with high bandwidth and large amplification ratio

Micro-displacement amplifiers show great potential for enhancing the performance of piezoelectric ceramic stacks. However, designing a compact micro-displacement amplifier with a high amplification ratio and broad bandwidth remains challenging. This article introduces a hydraulic micro-displacement amplifier driven by a piezoelectric ceramic stack with a large amplification ratio, high bandwidth, and eliminating parasitic displacement. Theoretical and simulation analyses are performed for the hydraulic micro-displacement amplifier, optimizing parameters such as edge thin ring thickness and spring stiffness. A prototype was fabricated and tested in a series of experiments. The experimental results demonstrate that, under steady-state conditions, the hydraulic micro-displacement amplifier achieves an amplification ratio of 26.12 with a standard deviation of 2.28. The maximum output displacement is 172.4 μm at 150 V, and the resonant frequency is 445 Hz under a 20 N load. This study provides a novel approach to designing micro-displacement amplifiers.

Fusion Design of Cryogenic Filtering Low-Noise Amplifier With High Out-of-Band Rejection Assisted by Grey Wolf Optimizer

Fusion Design of Cryogenic Filtering Low-Noise Amplifier With High Out-of-Band Rejection Assisted by Grey Wolf Optimizer

Issues and Challenges in Small-Signal Low-Power Amplifiers: A Review

Background: Contemporary linear electronic circuit designs frequently include small-signal low-power amplifiers as a fundamental building block. These amplifiers are widely used as LNAs (Low Noise Amplifiers) in the pre-amplifier stages of both low-frequency and high-frequency featured electronic circuits. Objectives: To review the recent advances in the design of small-signal low-power amplifiers based on device configuration of BJTs, JFETs and MOSFETs for low (≤1KHz) and high frequencies (≥1MHz) at smaller input voltage (<1 Volt). Methods: The articles published between 2010 to 2024 are shortlisted from IEEE Xplore, Springer, Science Direct Elsevier, Google Scholar, and MDPI databases and the outcomes of the different techniques are compared on various parameters. Findings: It is found that four-stage CMOS amplifier at TSMC 40nm process technology emerges with highest 84.59dB gain, InP (Indium Phosphide) Distributed Amplifier Using 3-D Interdigital Capacitors carries widest bandwidth of 160 GHz, two stage darlington pair amplifier at 0.18μm under dual input and dual output topologies and four stage CMOS amplifier at 40nm technology realizes lower power consumption of 0.5mW and 0.00086 mW respectively. Small Signal Amplifier based on single stage BJT-JFET Sziklai pair operates at lowest frequency of 11.36 Hz, single stage LNA at 180nm CMOS technology using inductive degenerate topology works at very low supply voltage at +0.5V and, recently reported complementary sziklai based small signal amplifier under CC mode works at lowest -15V supply voltage. Novelty: The review proposed on ‘Small Signal Low Power Amplifier’ is first time reported in this paper. Moreover, it discusses low power small signal amplifiers at both low (≤1KHz) and high (≥MHz) frequencies considering gain enhancement technique, power dissipation reduction technique, and noise reduction technique whereas other review papers emphasize on the general discussion of different topologies only at high frequencies. Keywords: Small-Signal Amplifiers, Low Power Amplifiers, BJTs, JFETs, MOSFETs

Kilowatt-Level High-Efficiency Narrow-Linewidth All-Fiber Tm3+-Doped Laser

In this study, a kilowatt-level high-efficiency narrow-linewidth all-fiber Tm3+-doped continuous-wave laser operating at 1.95 μm is demonstrated. Benefitting from an advanced boost design of a two-stage main amplifier, it not only effectively manages heat dissipation resulting from the high pump-induced quantum defect but also realizes the controlled extraction of optical gain and improves the optical conversion efficiency. Finally, this laser system has realized an output power of 1018 W, a linewidth of 3.8 GHz, and a slope efficiency of 60.0% simultaneously. Moreover, a high optical signal-to-noise ratio of over 45 dB and excellent beam quality of M2 factors 1.19 are obtained. To the best of our knowledge, this represents the narrowest linewidth and highest slope efficiency achieved in a kilowatt-level Tm³⁺-doped fiber laser. Such a high-performance laser is ideally suited for mid-infrared generation and remote sensing applications.