Analog Switch Research Articles

Enhanced analog switching and neuromorphic performance of ZnO-based memristors with indium tin oxide electrodes for high-accuracy pattern recognition.

This study systematically investigates analog switching and neuromorphic characteristics in a ZnO-based memristor by varying the anodic top electrode (TE) materials [indium tin oxide (ITO), Ti, and Ta]. Compared with the TE materials (Ti and Ta), memristive devices with TEs made of ITO exhibit dual volatile and nonvolatile switching behavior and multistate switching characteristics assessed based on reset-stop voltage and current compliance (ICC) responses. The polycrystalline structure of the ZnO functional layer sandwiched between ITO electrodes was confirmed by high-resolution transmission electron microscopy analysis. The current transport mechanism in the ZnO-based memristor was dominated by Schottky emission, with the Schottky barrier height modulated from 0.26 to 0.4V by varying the reset-stop voltage under different ICC conditions. The long-term potentiation and long-term depression synaptic characteristics were successfully mimicked by modulating the pulse amplitudes. Furthermore, a 90.84% accuracy was achieved using a convolutional neural network architecture for Modified National Institute of Standards and Technology pattern categorization, as demonstrated by the confusion matrix. The results demonstrated that the ITO/ZnO/ITO/Si memristor device holds promise for high-performance electronic applications and effective ITO electrode modeling.

DC voltage switching-based octuple-electrode microdevice for cell rotation and area-specific membrane capacitance measurement

Single-cell electrorotation plays an important role in the field of single-cell imaging and electric parameter measurement. However, reported cell rotation technology often adopts a quadruple-electrode structure and is excited by an AC signal. The distribution of electric field strength in the enclosed area is not uniform, and the rotation speed of the cells is related to the location in the area, so it is difficult to achieve uniformity of electric field distribution and the stationarity of rotation. This work proposes a DC voltage switching-based octuple-electrode microdevice for cell rotation and area-specific membrane capacitance measurements. This design can switch the DC voltages on each electrode periodically to produce a uniformly distributed rotating electric field. The rotation direction of the electric field can be realized by simply controlling the switching order of the analog switches. According to the theoretical single-cell model, the area-specific membrane capacitance of cells are determined through rotation movements. Simultaneously, based on simulation results, the rotation area is normalized to enhance the accuracy of the measuring electrical parameters. This study demonstrates the potential application of the proposed octuple-electrode DC voltage-based electro-rotation device for rapid, convenient, and cost-effective manipulation and electrical parameter measurement of single cells.

Single-photon elimination in liquid scintillation counting with pulse shape discrimination and delayed coincidence

Liquid scintillation counting is widely used in the rapid measurement of beta activity in environmental and biological samples. However, the single-photons generated by chemiluminescence and photoluminescence in liquid scintillation cocktails seriously affect the measurement accuracy of low-energy beta activity. A novel method based on the combination of the signal characteristic analysis and selective gate to eliminate the single-photon signal was developed. A preprocessing circuit made of a fast response time photomultiplier tube (PMT, Hamamatsu R9420), two charge-sensitive preamplifiers (CSP), two comparators, an analog switch and delay-line devices were designed and developed to verify the feasibility and effectiveness. The output signals from the last dynode were characterized in the pulse time and were used to discriminate the beta signals from the single-photon ones. The beta signals were “tagged” through pulse width detection, pulse width-amplitude transform and pulse-height discrimination with the first comparator, the first CSP and the second comparator. The “tagged” beta signal were applied to control the analog switch. The anode signals were specially delayed and then selected by the analog switch to achieve the single-photon signal elimination. Liquid scintillation cocktails containing 14C or NaOH used as beta or single-photon sources were provided to verify the feasibility of the principle. The results showed that the typical fall time of the single-photon and beta signal was 16.05ns and 43.17ns. The single-photon rejection ratio is 2.76 × 10−3 ± 3.89 × 10−5, and the detection efficiency is up to 93.02%±0.59%.

Analog and digital resistive switching in W/TiO2/ITO devices: the impact of crystallinity and Indium diffusion

The resistance-switching memristor with capabilities of information storage and brain-inspired computing has prime importance in recent research. In this study, the impact of crystallinity and Indium diffusion on the existence of analog and digital resistive switching in a W/TiO2/ITO device has been reported. The memristor devices are fabricated by depositing titania films by sol–gel and spin-coating techniques. The films annealed at 250 °C and 400 °C were characterized using x-ray diffraction, Raman spectroscopy, scanning electron microscopy, and x-ray photoelectron spectroscopy (XPS). The characteristic anatase phase started appearing after annealing at 400 °C, whereas the 250 °C annealed sample was in the amorphous state. The electrical characterization revealed significant differences in the switching characteristics of amorphous and crystalline samples, especially in the switching interface, compliance properties, and current conduction mechanism. The grain boundary assisted oxygen vacancy migration, and the diffusion of indium ions from the ITO bottom electrode helped the crystalline sample to show highly stable and reproducible resistive switching compared to amorphous film. The XPS studies confirmed the indium ion diffusion in the crystalline sample. The oxygen vacancy-induced barrier modulation and conductive filament formation caused characteristic switching in amorphous and crystalline samples, respectively. Schottky emission in the amorphous film and SCLC mechanism in the crystalline film confirmed the experimental results. This study provides a distinctive viewpoint and an innovative strategy for developing multifunctional resistive switching devices.

An analog switch circuit structure suitable for low-distortion transmission

Abstract A MOSFET analog switch circuit structure suitable for low-distortion bidirectional signal transmission is proposed. By introducing a “threshold voltage matching MOSFET” into the MOSFET switch driver circuit structure, the driving voltage corrected by the threshold voltage is generated by the driving circuit, eliminating the problem of poor conduction on-resistance flatness in traditional analog switch circuit structure due to MOSFET second-order effects and non-constant overdrive voltage. The circuit completed schematic and layout design based on the 0.13 μm BCD process. Simulation results show that the switch has bidirectional transmission capability, with a typical on-resistance value of 115 Ω. It achieves less than 5% on-resistance non-flatness under resistive loads ranging from 500 Ω to 1 KΩ, which is more than 50% improvement compared to traditional analog switch structures. Moreover, the on-resistance flatness is insensitive to changes in load and temperature.

The use of non-invasive tomographic imaging to monitor lung condition

The development of ultrasound tomography (UST) aimed to significantly enhance the precision and safety of non-invasive UST imaging, particularly for studying crystallization processes in biological tissues. The initiative sought to address the limitations of previous versions by incorporating advanced technological upgrades and providing a more user-friendly interface. The revised system comprises eight four-channel measurement cards interconnected via a high-speed FD CAN bus capable of 8 MBPS data transfer. Each card features a dedicated square wave generator, band-pass filters tailored to specific ultrasonic transducer frequencies, and a sophisticated signal envelope processing unit. The core processing unit is built around a 32-bit STM32G474RE microcontroller, ensuring robust data handling and image reconstruction capabilities. The UST device presented demonstrates improved image clarity and reduced noise interference. The measurement card redesign has achieved a sampling rate of 4 MBPS per channel and includes a two-stage amplification for dynamic range management. Upgraded power components, comprehensive shielding, and the integration of advanced analog switches have led to an enhanced signal-to-noise ratio, pivotal for high-resolution imaging. The advancements presented in the UST device mark a noteworthy progression in ultrasound imaging technology, extending beyond traditional applications. High-speed data collection, precise signal processing, and user-centered design have all come together to make a system that can image crystallization processes more accurately and accurately over and over again.

Organic heterojunction memristors with enhanced tunable resistive states for artificial synapses

Tunable and uniform evolution of conductance is the key performance metric for neuromorphic computing leveraging memristors. Nonetheless, the stochastic conductance update associated with limited material composition and uncontrollable filament distribution has restricted the tunability that can be customized for targeted synaptic properties. Here, we introduce organic heterojunction memristors utilizing the C60/P3HT bilayer, demonstrating analog switching characteristics with multilevel conductance states. We demonstrate that both conventional bipolar and unipolar voltages can achieve synaptic plasticity modulation for potentiation and depression, offering enhanced tunability. Through in situ Raman spectroscopy and impedance spectroscopy, we directly observe the dynamic alterations within the active layers during switching processes. The reversible migration of ions diminishes the barrier within the polymer layer, leading to highly uniform resistive switching behavior. The C60 layer functions as a confined transport medium, mitigating critical current variability issues. Moreover, we introduce a shunt resistor approach, furnishing analog memristors with selectively adjustable uniformity, enhanced linearity, and expanded dynamic conductance range, providing a general solution adaptable to various memristive hardware architectures.

Design of SEE-Tolerant analog switch chip with a novel diode structure *

This paper proposes a novel circuit-level design in order to enhance the radiation tolerance of an analog switch integrated circuit. After analyzing the mechanisms of single-particle sensitivity in a high-voltage analog switch chip fabricated using a commercial 1 μm complementary metal–oxide–semiconductor process, a diode unit was employed to reduce the V GS (voltage between the gate and the base) of the parasitic triode within the metal–oxide–semiconductor field-effect transistor of the switch. This reduction lowered the probability of activating the parasitic triode in response to single-event effect (SEE). Subsequently, single-particle irradiation experiments proceeded with the high-voltage analog switch chip, both with and without the diode unit. In the unreinforced device, the current of the power supply reached 100 mA within 11 s of single-particle irradiation at 75.8 MeV•cm2 mg−1. In contrast, in the reinforced device, the current of the power supply remained relatively stable under irradiation at both 37.2 and 75.8 MeV•cm2 mg−1. These findings indicate that the reinforced analog switch chip exhibits an SEE tolerance exceeding 75.8 MeV•cm2 mg−1, highlighting its potential to enhance the radiation tolerance of analog switches.

(Invited) Electrochemical Random Access Memory for Neuromorphic Computing

Electrochemical random access memory (ECRAM) is a three terminal device that functions by tuning electronic conductance in functional materials through solid-state electrochemical redox reactions, and is one of several emerging device concepts that are currently being investigated in academic and industrial laboratories for enabling energy efficient brain inspired computing. Early demonstrations of nearly ideal analog switching and the realization that electrochemical ion insertion can be used to tune the electronic properties of many types of materials including transition metal oxides, layered 2D material, organic and coordination polymers, has sparked tremendous interest in ECRAM. Depending on the specific material, the resulting changes in conduction can range from gradual increments needed for analog elements, to large, abrupt changes for dynamically reconfigurable adaptive architectures. At its core, ECRAM shares many fundamental aspects with rechargeable batteries, where ion insertion materials are used extensively for their ability to reversibly store charge and energy. Computing applications, however, present drastically different requirements: systems will require many millions of devices, scaled down to less than 100 nanometers, all while achieving reliable electronic-state tuning at scaled-up rates (~109 Hz) and endurances (>1012 cycles), and with minimal energy dissipation and noise. In my presentation, I will briefly cover the history of ECRAM, the recent progress in devices spanning various types of materials, circuits, architectures, and discuss the rich portfolio of challenging, fundamental questions and how we can harness ECRAM to realize a new paradigm for low power neuromorphic computing.

A fully floating memristor emulator with long-term memory

In this paper, we proposed a fully floating memristor emulator with long-term memory characteristics. The circuit comprises operational amplifiers and an analog switch. Switching between incremental and decremental modes is easily achieved by changing the polarity of the input signal. The key feature of the emulator is its long-term memory, made possible by the switch and voltage follower. The correctness of the derived formula is verified using Matlab, and the emulator's pinched hysteresis loop and non-volatility are assessed using LTspice. Additionally, an experimental platform was constructed for physical testing, with the physical results showing consistency with the simulations. Finally, the proposed emulator was applied to a simple read-write circuit, demonstrating its practical applicability.

Electrically Reconfigurable Phase-Change Transmissive Metasurface.

Programmable and reconfigurable optics hold significant potential for transforming a broad spectrum of applications, spanning space explorations to biomedical imaging, gas sensing, and optical cloaking. The ability to adjust the optical properties of components like filters, lenses, and beam steering devices could result in dramatic reductions in size, weight, and power consumption in future optoelectronic devices. Among the potential candidates for reconfigurable optics, chalcogenide-based phase change materials (PCMs) offer great promise due to their non-volatile and analogue switching characteristics. Although PCM have found widespread use in electronic data storage, these memory devices are deeply sub-micron-sized. To incorporate phase change materials into free-space optical components, it is essential to scale them up to beyond several hundreds of microns while maintaining reliable switching characteristics. This study demonstrated a non-mechanical, non-volatile transmissive filter based on low-loss PCMs with a 200 × 200 µm2 switching area. The device/metafilter can be consistently switched between low- and high-transmission states using electrical pulses with a switching contrast ratio of 5.5 dB. The device wasreversibly switched for 1250 cycles before accelerated degradation took place. The work represents an important step toward realizing free-space reconfigurable optics based onPCMs.

A Low Mismatch Current Charge Pump Applied to Phase-Locked Loops.

This paper presents a charge pump circuit with a wide output range and low current mismatch applied to phase-locked loops. In this designed structure, T-shaped analog switches are adopted to suppress the non-ideal effects of clock feedthrough, switching time mismatch, and charge injection. A source follower and current splitting circuits are proposed to improve the matching accuracy of the charging and discharging currents and reduce the current mismatch rate. A rail-to-rail high-gain amplifier with a negative feedback connection is introduced to suppress the charge-sharing effect of the charge pump. A cascode current mirror with a high output impedance is used to provide the charge and discharge currents for the charge pump, which not only improves the current accuracy of the charge pump but also increases the output voltage range. The proposed charge pump is designed and simulated based on a 65 nm CMOS process. The results show that when the power supply voltage is 1.2 V, the output current of the charge pump is 100 μA, the output voltage is in the range of 0.2~1 V, and the maximum current mismatch rate and current variation rate are only 0.21% and 1.4%, respectively.

Engineering of TiN/ZnO/SnO2/ZnO/Pt multilayer memristor with advanced electronic synapses and analog switching for neuromorphic computing

The two-terminal memristor is a promising neuromorphic artificial electronic device, mirroring biological synapses in structure and replicating various synaptic functions. Despite its advantages, challenges in achieving high reliability, gradual switching, and low energy consumption hinder progress in neuromorphic devices. This study explores electronic synapses and simulates analog switching in a Pt/TiN/ZnO/SnO2/ZnO/Pt multilayer (ML) configuration, featuring a ∼3 nm SnO2 layer between ZnO layers. Results show enhanced cycling endurance (more than 250 cycles), resistance window (102), tunable synaptic plasticity, and multilevel switching. ML memristors exhibit low coefficient of variation (4.5 %) in set voltage, low energy consumption (set = ∼0.12 nj, reset = ∼0.1 nj), and fast switching speeds (set = 300 ns, reset = 200 ns), suitable for high-density memory and neuromorphic systems. They successfully emulate synaptic functions, including paired-pulse facilitation (PPF), spike voltage-dependent plasticity (SVDP), spike width-dependent plasticity (SWDP), spike frequency-dependent plasticity (SFDP), and post-tetanic potentiation (PTP). Modulating pulse amplitude and width achieves multilevel conductance in long-term potentiation (LTP) and long-term depression (LTD). Using nonlinear conductance data, a 96.5 % image pattern recognition accuracy is achieved in a deconvolution neural network (DNN) simulation. These results highlight the ML memristor's potential in efficient neuromorphic computing systems.

Compliance-free, analog RRAM devices based on SnOx

Brain-inspired resistive random-access memory (RRAM) technology is anticipated to outperform conventional flash memory technology due to its performance, high aerial density, low power consumption, and cost. For RRAM devices, metal oxides are exceedingly investigated as resistive switching (RS) materials. Among different oxides, tin oxide (SnOx) received minimal attention, although it possesses excellent electronic properties. Herein, we demonstrate compliance-free, analog resistive switching behavior with several stable states in Ti/Pt/SnOx/Pt RRAM devices. The compliance-free nature might be due to the high internal resistance of SnOx films. The resistance of the films was modulated by varying Ar/O2 ratio during the sputtering process. The I–V characteristics revealed a well-expressed high resistance state (HRS) and low resistance states (LRS) with bipolar memristive switching mechanism. By varying the pulse amplitude and width, different resistance states have been achieved, indicating the analog switching characteristics of the device. Furthermore, the devices show excellent retention for eleven states over 1000 s with an endurance of > 100 cycles.

Coexistance of the Negative Photoconductance Effect and Analogue Switching Memory in the CuPc Organic Memristor for Neuromorphic Vision Computing.

A bioinspired in-sensing computing paradigm using emerging photoelectronic memristors pursues multifunctionality with low power consumption and high efficiency for processing large amounts of sensing information. An organic semiconductor memristor strategy based on the CuPc functional layer integrates a negative photoconductance (NPC) effect and an analogue switching memory (ASM) effect in the same pixel. The NPC effect, present in the pure capacitance state at low bias voltage, provides high-performance short/long-term synaptic plasticity modulable by light pulse parameters. The interface charge effect along with defeat site trapping and detrapping is responsible for the pure capacitance effect and the NPC effect, with electron tunneling and electric-field-driven band dynamics responsible for ASM. This work reveals an organic memristor approach for hardware implementation of a neuromorphic vision computing system, emulating retinal bipolar cells via light-dominated NPC and electrically induced ASM with stable, tunable conductance states.

Synaptic behavior in analog memristors based on green-synthesized ZnO nanoparticles

In this work, spherical-like ZnO nanoparticles (NPs) were synthesized via avocado seed extract and calcined at 400 °C, which exhibited a hexagonal wurtzite structure with an average size of around 42 nm. The chemical states, organic residuals, and defects were confirmed by X-ray photoelectron spectroscopy (XPS). The ZnO NPs-based memristors exhibited remarkably stable analog switching, over 300 continuous cycles, and a wide operating window of 400. Moreover, the asymmetry in the current observed was attributed to the self-rectifying nature of this device, comprising one analog memristor and one Schottky diode (1D–1R). By controlling the peak voltage to 4 V and applying 50 bias pulses, it was possible to effectively imitate the key features of synaptic behavior, including potentiation and depression, through current modulation.

Synthesis of composite films for ZnO-based memristors with superior stability

Memristors have unique non-volatile characteristics that potentially can emulate biological synapses for applications in neural computing systems. However, the random formation of conductive filaments in these devices can cause various unreliability problems. In this work, films of a composite of ZnO nanoparticles and carbon nanotubes were prepared as functional layers for memristors by an in-situ growing strategy (ZnO@CNT-IS) using a straightforward high-temperature annealing treatment. This approach allowed for the formation of a high-quality films with uniform loading of ZnO nanoparticles on the carbon nanotubes, which contributed to a lower formation energy for oxygen vacancies and increased electron transfer rate. As a result, the memristors exhibited faster switching response speed, lower power consumption, and a stabilised switching ratio even after 2000 switching cycles. Based on the analog switching behaviour, the ZnO@CNT-IS-based devices showed significant biological synapse functions and plasticity, indicating their potential for high-density storage and neuromorphic computing.

Smart solutions in car dashboard interfaces as a response to needs of drivers and their assessment

Current trends in the production of passenger cars focus on the development of the so-called intelligent cars, richly equipped with multimedia systems with uninterrupted access to the Internet, connected to digital road infrastructure leading to autonomous driving in the future. Such changes lead to the development of new solutions and testing them, first in laboratory conditions, and then in practical use with the participation of consumers, and especially drivers. Vehicle designers are guided by the idea of simplifying vehicle interfaces’ operation and making them more comfortable and easier to use, while maintaining safety standards for traveling people and other road users. However, the question arises whether they actually achieve the expected results. The authors of the work focused on selected solutions and on assessing the validity of using such solutions in terms of convenience and safety. Various factors influencing drivers' driving behavior were discussed, mainly related to media handling. The research was based on a survey questionnaire containing a number of questions addressed to people using particular systems. Vehicle users expressed their opinions on three solutions available on the market used in car cockpits (ASD – analogue switch dashboards, GSD – gesture/speech controlled dashboards, and TSD – touch screen dashboards). The analysis of the collected data made it possible to clarify the extent to which the use of the car cockpit is adapted to the actual needs of the users. In order to qualitatively evaluate the research results, correspondence and decision tree analyzes were used. The obtained results indicate significant differences in the assessment of communication interface solutions in groups of respondents due to different grouping variables.

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The implementation of digital broadcasting policies in Indonesia was marked by the issuance of Law Number 11/2020 concerning Job Creation, which was followed by the migration from analog to digital broadcasting (Analog Switch Off/ASO). The dynamics of digital broadcasting are caused by the tug of war-between the legislative, executive, judiciary, academics, nongovernmental organizations, and the broadcasting media industry itself. What is the policy of digital broadcasting after the implementation of Law Number 11/2020 concerning Job Creation, especially Article 60 A regarding ASO on November 2, 2022? What are the opportunities and challenges that communication-based tertiary institutions have in utilizing digital broadcasting in Indonesia? The paradigm of this research is qualitative. Data collection techniques through observations on digital broadcasting business trends, interviews, and legal studies. As a result, the digital broadcasting policy has been running quite well so far. Although implementation in each field is constrained by various problems: infrastructure, infraculture, human resources, and the extent of territory. Findings found that higher education institutions must be able to take advantage of opportunities for digital broadcasting policies as a means of disseminating information. The latest research results indicate that universities can establish digital television companies or content providers as well as a place for distributing work for college graduates. Keywords: Broadcasting, digital, ASO, universities, policy.

Digital education community TV existence in post analog switch off

Background: Based on Law (UU) Number 11 of 2020 regarding Cipta Kerja or the Omnibus Law, broadcasting institutions should switch from terrestrial or analog broadcasts to digital broadcasting via Analog Switch Off (ASO), which provides opportunities for community TV to develop. UGTV is Indonesia’s first digital education community TV to broadcast cultural and education-based programs. Purpose: To analyze the existence of UGTV as the first digital education community TV in Indonesia. Methods: Researchers distributed questionnaires to 144 respondents in Depok and 115 in Bekasi to determine the most popular programs. Researchers then conducted interviews with UGTV staff and leaders and compared the quality of UGTV programs based on KPI standards. Results: Based on the research results, UGTV as Indonesia’s first digital educational community television has met all KPI standards by offering some programs such as Team Teaching and Info Kampus. The types of broadcast programs in the form of tourism and cultural programs are still in demand and influence the audience’s viewing interest. Based on qualitative analysis as a follow-up analysis, the public response in these three areas is currently low because people have many new media choices that can be accessed easily at lower costs. Conclusion: The public feels that television lacks “interesting” shows so the existence of UGTV and other community channels can become a choice for the audience. Implications: KPI and KPID must actively monitor and develop broadcast content by collaborating with community broadcasting institutions so that broadcast production can be more varied.