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In this work, a single active element (Extra-X Current Controlled Conveyor) with grounded capacitor is used to design a reconfigurable first-order universal filter (CFUF). By simply swapping the digital control words (k1k2), the suggested circuit may implement all of the common filter responses, including high-pass, low-pass, and all-pass. An EX-CCCII serves as the active element in the filter setup, which is based on a novel topology, which provides several advantages, such as reduced complexity, low power consumption, and improved performance. The following advantages of the proposed circuit: high input impedance for voltage input signals, electronically controllable pole frequency that varies with bias current, and a single grounded capacitor that can be integrated into an IC. At a power supply level of ±0.5 V, the proposed circuit is modeled using specifications for 0.18-micrometer CMOS technology. PSPICE simulation tool is used to demonstrate the filter's performance. [ABSTRACT FROM AUTHOR]

In this work, a new versatile voltage- and transconductance-mode analog filter is proposed. The filter, without requiring resistors, employs three differential-difference transconductance amplifiers (DDTAs) and two grounded capacitors, which is suitable for integrated circuit implementation. Unlike previous works, the proposed filter topology provides: (1) high-input and low-output impedances for a voltage-mode (VM) analog filter, that is desirable in a cascade method of realizing higher order filters, and (2) high-input and high-output impedances for a transconductance-mode (TM) analog filter without any circuit modification. Moreover, a quadrature oscillator is obtained by simply adding a feedback connection. Both VM and TM filters provide five standard filtering responses such as low-pass, high-pass, band-pass, band-stop and all-pass responses into single topology. The natural frequency and the condition of oscillation can be electronically controlled. The circuit operates with 0.5 V supply voltage. It was designed and simulated in the Cadence program using 0.18 µm CMOS technology from TSMC. [ABSTRACT FROM AUTHOR]

In this paper, new Gm-C all-pass and amplitude-equalizer biquads are shown to be realized from a generalized Gm-C biquad filter structure by using Gm-simulated negative resistor in series with integrating capacitor in the lossless integrator. The non-ideality analysis of the all-pass/ amplitude-equalizer biquad using finite output conductance and parasitic output capacitance of Gm-cells is presented. The proposed Gm-C all-pass and amplitude-equalizer biquads are simulated for 0.18 μm CMOS technology with ± 0.9 V power supply in Cadence environment to validate the frequency response characteristics. For the Gm-C AP biquad filter designed for 1 MHz cut-off frequency and pole quality factor of 2, the power consumption is 82.37 µW, the input-referred noise is 137.6 μ V / H z and the dynamic range is 62.84 dB. The biquad has the figure of merit (FoM) of 0.2969 × 10−13 J. [ABSTRACT FROM AUTHOR]

A new realisation of an electronically tunable first-order voltage-mode all-pass filter enjoying the feature of low voltage and low power is proposed in this paper. The proposed realisation of filter employs only one active element namely differential voltage extra-x current controlled conveyor and one grounded capacitor. The use of minimal number of components makes the proposed structure simple and attractive from chip fabrication point of view. The performance of proposed structure is also discussed by considering the effects of parasitic and non-idealities of the used active element. Additionally, higher order filter realisation is also included to enrich the presented work by exploring possible applicability aspects. The theoretical performance is validated at schematic level using 0.18 µm CMOS technology parameters with ±1 V supply voltages. Furthermore, Cadence Analog Design Environment (ADE) with gpdk 0.18 µm technology is used to design the layout of the proposed circuit. Pre-layout and post-layout simulation verification is provided to extend the real time validation of theoretical aspects. [ABSTRACT FROM AUTHOR]

In this study, MOS-Only transimpedance mode filters are proposed. The presented circuits use two capacitors and MOS transistors that operate in saturation mode. The circuits are additional examples contributing to the set of previously published circuit topologies. One of the circuits is chosen and its functionality is verified with simulations. An important aspect of the chosen design is the versatility of filter parameters. Changing the drain currents of MOSFETs makes it possible to adjust the center frequency after production. We performed simulations with the LTSPICE simulation program using 0.18 μm TSMC CMOS technology. Simulation results are found in close agreement with the theoretical results. [ABSTRACT FROM AUTHOR]

An improved class AB version of the super source follower is used to implement a compact and power-efficient second order analog low-pass filter. The proposed circuit achieves a 41% power reduction as well as an improvement in linearity and pass band gain with respect to its class A counterpart. Measurement results of a test chip prototype fabricated in a 180 nm CMOS technology show a power consumption ranging from 50.3 $\mu \text{W}$ to 85.27 $\mu \text{W}$ for cutoff frequencies from 600 kHz to 890 kHz, with a supply voltage of ±0.75 V. A third order intermodulation distortion of −35.34 dB (for an input signal of 0.4 mVpp and 350 kHz) and a THD of −69.7 dB (for an input signal of 0.4 mVpp and 100 kHz) are measured, which results in an improvement with respect to the conventional class A version of 13.98 dB and 43.6 dB, respectively. The silicon area is 0.0592 mm2 (using external capacitors). [ABSTRACT FROM AUTHOR]

This brief presents the analysis, design, and measurements of a compact analog frontend for a catheter-integrated ultrasound imaging digitizer. This frontend requires several functions, including single-ended-to-differential conversion, AC coupling, amplification, anti-aliasing, and the capability to drive the subsequent ADC. To minimize chip area and to maximize power efficiency, a 2-stage frontend was designed, where the active stages are built using self-biased inverter-based amplifiers. The measured prototype in 40nm CMOS offers a gain of up to 15dB and a bandwidth up to 20MHz, while consuming up to $162\mu \text{W}$ from a 1.1V supply. The peak FoM of 158dB(J−1) and chip area of 0.0054mm2 are in line with state-of-the-art filters, while the proposed design includes the aforementioned extra functionalities as well. [ABSTRACT FROM AUTHOR]

This paper introduces a simulated grounded inductor (SGI) circuit realization based on two terminal active devices, namely negative impedance converters. The proposed SGI contains a minimum number of passive components when compared to its two terminal active device-based realization counterparts in the literature. It includes a grounded capacitor that is an advantage in integrated circuit process. Nonetheless, a single resistive matching constraint is needed for its realization. SPICE simulations are performed with 0.13 µm CMOS IBM technology parameters with supply voltages of ± 0.75 V. Also, an experimental study is included to verify the theory. [ABSTRACT FROM AUTHOR]

In this paper, an electronically tunable mixed-mode analog filter is proposed, which employs only a single active element, namely Extra X Current Controlled Conveyor (EX-CCCII), two capacitors and a single resistor. The proposed circuit uses minimum components, so it is easy to integrate on chip. The circuit provides all four mode operations, namely current mode, voltage mode, transadmittance mode (TAM) and transimpedance mode without changing the circuit configuration. The circuit can provide all the five filter functions: low pass, high pass, band pass, band reject, and all pass by selecting appropriate input signals except the TAM. The parameters of the proposed circuit, i.e. angular frequency (ωo) and the quality factor (Q) are independent, while ωo is electronically tunable. The frequency range is 2.29 MHz to 22.9 MHz with a bias current variation from 1 to 100 µA. The effects of non-idealities and parasitics of the active element on the circuit performances are discussed. The results are verified through PSPICE simulation using a 0.18 µm CMOS technology with the supply voltages of ± 0.5 V. The power consumption is 13.5 µW at 1 µA, and 1.35 mW at 100 µA. The experimental setup further validates the theory and simulation results. [ABSTRACT FROM AUTHOR]

This paper presents a differential fourth-order low-pass filter suitable for electrocardiography (ECG) acquisition. It is formed by cascading two compact and power-efficient biquads operating in the subthreshold region. Each biquad combines two capacitors and a flipped voltage follower circuit. The filter attains a cutoff frequency adjustable to cover the entire range of ECG (150–250 Hz). The filter prototype has been fabricated in a 0.35- $\mu \text{m}$ CMOS technology. It occupies an area of $362\,\,\mu \text {m} \times 466 \,\,\mu \text{m}$ and operates from a 0.6-V supply. Measurements confirm that the filter consumes 0.9-nW static power for a 101-Hz cutoff frequency and contributes the input-referred noise of 46.27 $\mu \text{V}_{\mathbf {rms}}$. For a 60-Hz input frequency, the filter achieves a dynamic range of 47 dB where the third-harmonic distortion of −60 dB is produced. This leads to the figure of merit of $46.5 \times 10^{-18}$ J. When the chip area is also concerned, the proposed filter performs comparably to the recent state-of-the-art nanowatt-class low-pass filter. [ABSTRACT FROM AUTHOR]

This paper deals with a single-input multiple-output biquadratic filter providing three functions (low-pass, high-pass and band-pass) based on voltage differencing differential input buffered amplifier (VD-DIBA). The quality factor and pole frequency can be electronically tuned via the bias current. The proposed circuit uses two VD-DIBAs and two grounded capacitors without any external resistors, which is suitable to further develop into an integrated circuit. Moreover, the circuit possesses high input impedance, providing easy voltage-mode cascading. It is shown that the filter structure can be easily extended to multi-input filter without any additional components, providing also all-pass and band-reject properties. The PSPICE simulation results are included, verifying the key characteristics of the proposed filter. The given results agree well with the theoretical presumptions. [ABSTRACT FROM AUTHOR]

This paper presents a new current-mode current-controlled four-input five-output universal filter employing one current-controlled current conveyor (CCCII), one electronically tunable CCCII and two grounded capacitors. The proposed configuration provides lowpass, bandpass, highpass, bandstop and allpass current responses that taken from the high-output impedance terminals, which enable easy cascadability of the current-mode operation. The filter also offers both orthogonal and electronic controls of the natural frequency and the quality factor through adjusting the bias current of the CCCIIs. For realizing all the filter responses, the proposed filter does not require passive component-matching condition and both active and passive sensitivities are low. In addition, a new current-mode current-controlled single-input five-output universal filter can be achieved by using an additional multiple-output minus-type CCCII The proposed filter is simulated using PSPICE simulations to confirm the theoretical analysis. [ABSTRACT FROM AUTHOR]

SUMMARY This paper presents an ultra-low-power fourth-order bandpass operational transconductance amplifier-C (OTA-C) filter for an implantable cardiac microstimulator used to detect the R-wave of intracardiac electrograms. The OTA-C filter fabricated by TSMC 0.35-µm complementary metal-oxide-semiconductor (CMOS) technology is operated in the subthreshold region to save power under a supply voltage of 1 V. The current cancellation technique is adopted to reduce the transconductance of the amplifier. Through this, the low-frequency OTA-C filter can be realized by ultra-low transconductance with on-chip capacitors. Direct comparison to conventional RLC ladders replaced by OTA-C circuits shows that the method of reducing the number of OTAs further diminishes power consumption. Design issues, including ultra-low transconductance, linearity, and noise, are also discussed. Measurement results show that the low-voltage, low-power filter has a bandwidth between 10 and 50 Hz, third inter-modulation distortion of −40 dB, dynamic range of 43 dB, and power consumption of only 12 nW. The real electrocardiography signal is fed into the bandpass filter to verify the function of signal processing with the distribution of the R-wave. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The configuration with electronic tunable characteristics that can work in mixed mode may be useful from IC realization viewpoint and application adaptability. This paper proposes an electronically tunable mixed mode universal filter based on multiple output current controlled current conveyor (MOCCCII) and this single topology without any alteration can be used in all four modes i.e., voltage (VM), current (CM), transimpedance (TIM) and transadmittance (TAM). The architecture uses four MOCCCIIs and two grounded capacitors; and can realize universal filter functions - low pass (LP), band pass (BP), high pass (HP), notch (NF) and all pass (AP) for all four modes. Moreover the input impedance is high and output impedance is low for voltage signal and vice-versa for current signal, hence the proposed topology is suitable for cascading for all four modes. The workability of the proposed circuit has been verified via SPICE simulations using AMS 0.35 μm CMOS technology. [ABSTRACT FROM AUTHOR]

This article presents a three-inputs single-output biquadratic filter performing completely standard functions: low-pass, high-pass, band-pass, band-reject and all-pass functions, based on current controlled current conveyor transconductance amplifier (CCCCTA). The quality factor and pole frequency can be electronically/independently tuned via the input bias current. The proposed circuit uses 2 CCCCTAs and 2 grounded capacitors without any external resistors which is very suitable to further develop into an integrated circuit. The filter does not require double input current signal. Each function response can be selected by suitably selecting input signals with digital method. Moreover, the circuit possesses high output impedance which would be an ideal choice for current-mode cascading. The PSPICE simulation results are included to verify the workability of the proposed filter. The given results agree well with the theoretical anticipation. [ABSTRACT FROM AUTHOR]

The differential current conveyor (DCCII) is a versatile current-mode active element, which has a current differencing capability. In this study, a new CMOS DCCII implementation is introduced. As an application example, a novel voltage-mode (VM) first-order all-pass filter (APF) is presented. The proposed VM APF employs two resistors, grounded capacitor and has high-input impedance for cascadability. Simulation and experimental results are given to verify the operation of the circuit. [ABSTRACT FROM AUTHOR]

In this study, two novel first-order all-pass filters are proposed using only one grounded resistor and one grounded capacitor along with a fully differential current conveyor (FDCCII). There is no element-matching restriction. The presented all-pass filter circuits can be made electronically tunable due to the electronic resistors. Furthermore, the presented circuits enjoy high-input impedance for easy cascadability. The theoretical results are verified with SPICE simulations. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a current-mode (CM) analog filter for simultaneously realizing high output impedance low-pass, band-pass and high-pass analog responses besides high output impedance notch and all-pass analog filter responses with interconnection of the relevant output currents, is presented. Also, two CM filters for simultaneously providing high output impedance universal filter responses are derived from the proposed one. All of the introduced CM topologies employ a canonical number of only grounded capacitors without requiring any resistors, and do not need critical component matching conditions. All of the developed circuits have low input impedance and high output impedance resulting in easy cascadability with other CM ones. Frequency dependent non-ideal gain and parasitic impedance effects on the performance of the presented first filter are investigated as examples. In order the show the performance of the filter and verify the theory, simulations are accomplished with SPICE program. [Copyright &y& Elsevier]

Abstract: A novel mixed-mode biquad filter based on MCCCIIs (multiple outputs current controlled conveyors) is presented. The filter structure presented simply contains five MCCCIIs, two grounded capacitors and can realize low-pass, high-pass, band-pass filter functions from the same topology, simultaneously. The circuit can be driven by voltage or current and its output can be voltage or current. The natural frequency and quality factor Q enjoy independent electronic tunability through adjusting the bias currents of MCCCIIs. Simulation results using real device parameters of transistors NR100N and PR100N are included to show the practical utility of the proposed circuit. [Copyright &y& Elsevier]

In this paper, a dual output current-mode biquad filter with band-pass and low-pass outputs using MOS transistors and capacitors is presented. In these type of filters MOSFETs operating in saturation mode are used instead of standard active elements and transconductances of these transistors are utilized instead of resistors. In the study a voltage controlled current source (VCCS) based core filter circuit is presented. This circuit is used as a starting point for the complete filter design. After VCCSs are replaced by MOSFETs biased for operating in saturation region, a resistorless MOSFET-C type filter circuit is obtained with only seven transistors and two grounded capacitors. Also, an agile filter application for secure communication is given to illustrate the functionality. [ABSTRACT FROM AUTHOR]

In this paper, an active-C circuit for realizing lossless floating inductor (FI) or series/parallel R–L impedances depending on the externally applied bias currents, is presented. The proposed simulator circuit employs only three plus-type second-generation current controlled conveyors (CCCII+s) as active elements and a single capacitor as passive element. SPICE simulation and experimental results are given to verify the theory. [ABSTRACT FROM AUTHOR]

This article presents a versatile voltage-mode (VM) biquad filter with independently electronic tunability. The proposed structure using one dual-output operational transconductance amplifier, three single-output operational transconductance amplifiers (OTAs) and two grounded capacitors was explored to derive a new VM quadrature oscillator with the independent control of the oscillation frequency and the oscillation condition. The proposed versatile VM biquad filter achieves nearly all of the main advantages: (i) simultaneous realizations of band-reject, band-pass, and low-pass from the same architecture, (ii) multiple-input and multiple-output functions, (iii) independent electronic adjustability of quality factor and resonant angular frequency, (iv) no resistor needed, (v) all input terminals with cascade functions, (vi) no additional inverting amplifier for input signals, (vii) using only grounded capacitors, and (viii) easy to implement a VM quadrature oscillator with independent electronically controlled oscillation frequency and oscillation condition. The proposed versatile VM biquad filter employs only four OTAs and two grounded capacitors. The active components of the proposed VM biquad filter are one less than that of recent reports. The proposed circuit also brings versatility and simplicity to the design of VM biquad filters and VM quadrature oscillators. Filters and oscillators with less active and passive components have the advantages of low cost, low power dissipation, low circuit complexity, and low noise. Commercially available integrated circuit LT1228 and discrete components can be used to implement the proposed OTA-based circuits. The simulation and experiment results validated the theoretical analysis. [ABSTRACT FROM AUTHOR]

In this paper, an area efficient CMOS first-order voltage-mode (VM) all-pass filter (APF) is proposed. The introduced resistorless MOS-only core circuit consists of three transistors only. For the design three transconductances and one gate-to-source capacitance of MOS transistors are sufficient instead of external passive resistors and capacitors, while the full implementation of the VM APF consists of 12 MOS transistors and one grounded capacitor only. Hence, the proposed circuit exhibits important features such as simplicity, permitting reduced chip area when integrated and wide operating frequency range compared to classical analog counterparts that require active elements employing large number of transistors. The theoretical results are in detail verified by numerous post-layout simulations using Cadence IC6 Spectre analog design environment. In the design, medium V th transistors with 1.8 V supply voltage were used and modeled by the TSMC 180 nm CMOS process parameters available in EUROPRACTICE IC Service design kit. The post-layout simulated pole frequency of the VM APF is 4.825 MHz, the implemented layout including metal-insulator-metal on-chip capacitor occupies an area of 31.1 μm × 39.5 μm, while the total power consumption of the filter is found to be only 92.57 μW. [ABSTRACT FROM AUTHOR]

This paper presents a versatile tunable voltage-mode biquadratic filter with five inputs and three outputs. The proposed filter enjoys five single-ended output operational transconductance amplifiers (OTAs) and two grounded capacitors. The filter can be easily transformed into a quadrature oscillator. The filter with grounded capacitors is resistorless and electronically tunable. Either a voltage-mode five-input single-output biquadratic filter or a voltage-mode single-input three-output biquadratic filter can be operated by appropriate selecting input and output terminals. In the operation of five-input single-output biquadratic filter, the non-inverting lowpass, non-inverting bandpass, inverting bandpass, inverting highpass, non-inverting bandreject, inverting bandreject, and non-inverting allpass filtering responses can be realized by appropriately applying the input voltage signals. In the operation of single-input three-output biquadratic filter, the non-inverting/inverting lowpass, bandpass and bandreject filtering responses can be realized simultaneously. The circuit provides independent adjustment of the resonance angular frequency and quality factor, high-input impedance, and no inverting-type input voltage signals are imposed. The application in quadrature oscillator exhibits independent electronic tuning characteristic of the oscillation condition and the oscillation frequency. The theoretical analysis has been verified through OrCAD PSpice and furthermore by experimental measurements. [ABSTRACT FROM AUTHOR]