Operational Transresistance Amplifier Research Articles

MOS-C KHN FILTER USING VOLTAGE OP AMP, CFOA, OTRA AND DCVC

MOS-C realizations of the Kerwin–Huelsman–Newcomb (KHN) circuit using the commercially available Voltage Operational Amplifier (VOA) and the Current Feedback Operational Amplifier (CFOA) are reviewed in this paper. Additional MOS-C KHN realizations using the Operational Transresistance Amplifier (OTRA) and the Differential Current Voltage Conveyor (DCVC) are also included. MOS-C realizations of the KHN circuit using CMOS operational amplifier, CMOS current feedback operational amplifier and CMOS operational transresistance amplifier are also given.Spice simulation results using 0.18 CMOS technology model from MOSIS are included together with detailed comparison tables to demonstrate the differences between MOS-C KHN circuits using both of the commercially available active building blocks and CMOS integrated building blocks. A comparison with the Gm-C KHN circuit is also included.

Current‐input OTRA Schmitt trigger with dual hysteresis modes

AbstractA simple current‐input Schmitt trigger is presented and implemented. It consists of one operational transresistance amplifier and a resistor. In addition, the circuit offers dual hysteresis mode operations within the same topology. The circuit operations are described. Experimental and simulation results are given to verify the theoretical analysis. Copyright © 2009 John Wiley & Sons, Ltd.

MOS-C TOW-THOMAS FILTER USING VOLTAGE OP AMP, CURRENT FEEDBACK OP AMP AND OPERATIONAL TRANSRESISTANCE AMPLIFIER

Several MOS-C realizations of the Tow-Thomas circuit using the commercially available voltage operational amplifier and the current feedback operational amplifier are reviewed in this paper. Additional MOS-C Tow-Thomas realizations using the operational transresistance amplifier and the differential current voltage conveyor are also included. MOS-C realizations of the Tow-Thomas circuit using CMOS operational amplifier, CMOS current feedback operational amplifier and CMOS operational transresistance amplifier are also given. Spice simulation results using 0.18 CMOS technology model from MOSIS are included together with detailed comparison tables to demonstrate the differences between MOS-C Tow-Thomas circuits using both of the commercially available active building blocks and CMOS integrated building blocks.

A modified CMOS differential operational transresistance amplifier (OTRA)

A modified CMOS realization of the differential operational transresistance amplifier (OTRA) is presented. A fair comparison with Mostafa and Soliman OTRA [Mostafa H, Soliman A. A modified CMOS realization of the operational transresistance amplifier. Frequenz 2006;60:70–6] shows that the modified differential OTRA provides better performance in most parameters. The OTRA is suitable for analog VLSI applications since it does not suffer from constant gain bandwidth product. Hence, it can exhibit wide bandwidth at high gain values. Moreover, an OTRA-based variable gain amplifier (VGA) is also introduced.

HISTORY AND PROGRESS OF THE TOW–THOMAS BIQUADRATIC FILTER PART II: OTRA, CCII, AND DVCC REALIZATIONS

The realization of the Tow–Thomas (TT) circuit using the Operational Transresistance Amplifier (OTRA) is reviewed. The circuit employs two OTRA, and all passive elements are floating as the original Tow–Thomas circuit. The Current Conveyor (CCII) TT circuits are reviewed next. The progress in the realization of the TT circuit using CCII is demonstrated clearly by summarizing eight different circuits. One of the circuits has the advantage of very high input impedance using all grounded resistors and capacitors. The Differential Voltage Current Conveyor (DVCC) as the active building block in realizing the TT circuit is also considered. Finally, current mode TT circuits using balanced output CCII are summarized. Top Spice (level 49), simulation results using technology SCN 05 feature size 0.5 μm from MOSIS vendor: AGILENT are included to demonstrate the magnitude and phase frequency response of the TT circuits. Additional simulation results for the total power dissipation, total harmonic distortion, intermodulation IM3, input and output referred noise spectral densities are also included for comparison purposes.

MOS-C single amplifier biquads using the operational transresistance amplifier

A configuration for the realization of voltage-mode second-order filters employing a single operational transresistance amplifier (OTRA) as the active element is presented. This topology can synthesize lowpass, highpass, bandpass, notch and allpass filtering functions. The presented filters are suitable for MOS-C implementation, yielding the filter parameters to be electronically tunable. Theoretical analysis is verified with PSPICE simulation.

Design of current‐mode MOSFET‐C filters using OTRAs

AbstractIn this paper, third‐order current‐mode MOSFET‐C filters that use operational transresistance amplifiers (OTRAs) with little parasitic capacitance effects are presented. On the basis of the proposed systematic method and design procedure, we can efficiently synthesize third‐order active filters with OTRAs along with simplified MOSFET resistor circuits, and all virtually grounded capacitors. Third‐order current‐mode Chebychev low‐pass and high‐pass filters are realized to verify the validity of the theoretical analysis. Experimental results employing commercially available current feedback amplifiers are also given. Copyright © 2008 John Wiley & Sons, Ltd.

Switch-controllable OTRA-based bistable multivibrators

Two bistable multivibrators based on the operational transresistance amplifier (OTRA) are presented. The first topology consists of only one OTRA and a positive feedback network. The second multivibrator utilises a single-pole double-throw (SPDT) switch along with a bias voltage source to shift the hysteresis loop into either the right-half-part or the left-half-part of the νi–νo plane. These two proposed circuits have a common attractive feature. That is, both clockwise and counter-clockwise hysteresis operations can be fulfilled with an additional SPDT switch connected to different configurations. In order to extend the applications, a general multiple-output configuration is also suggested. The presented bistable multivibrators are simple and versatile. The operation principles are described in detail. Theoretical analyses are verified by the experimental results on the prototype circuits.

Switch-Controllable OTRA-Based Square/Triangular Waveform Generator

A switch-controllable square/triangular waveform generator is presented. The circuit consists mainly of two operational transresistance amplifiers and three switches. The dc level of the triangular signal can be adjusted. Both inverting and noninverting mode operations can be fulfilled. A prototype circuit is implemented and experimental results are recorded to demonstrate its feasibility.

Realization of High-Order OTRA-MOSFET-C Active Filters

High-order linear transformation (LT) MOSFET-C active filters with reduced parasitic capacitance effects based on operational transresistance amplifiers (OTRAs) are presented in this paper. A systematic method is developed to realize voltage-mode LT OTRA-based filters efficiently. Based on the proposed design procedures, we can synthesize high-order filters with OTRAs with only MOSFET resistor circuits (MRCs) and virtual grounded capacitors. Signal processing circuits employing OTRAs have almost constant bandwidths because of the use of current-feedback configurations. A third-order Chebychev lowpass filter is demonstrated. HSPICE simulation results that confirm the theoretical analysis are obtained. Furthermore, the proposed circuits can be extended to higher-order filters.

A CRITERION OF A MULTI-LOOP OSCILLATOR CIRCUIT

Multi-loop feedback control has attracted considerable attention due to its simplicity and ease of implementation.1 In order to simplify the cumbersome analysis of a multi-loop circuit, the signal flow graph representation should be used rather than our familiar nodal analysis methods. This paper presents a criterion from the well-established Mason's formula for multi-loop oscillator in terms of signal flow graphs. The multi-loop oscillator circuit based on two operational transresistance amplifiers (OTRAs) is used as an example.

Single OTRA-based current-mode monostable multivibrator with two triggering modes and a reduced recovery time

A simple current-mode monostable multivibrator is introduced. The proposed topology consists of a single operational transresistance amplifier (OTRA) as a main active building block with a few external passive elements. The proposed circuit is simpler compared to counterparts composed of op amps and commercially available ICs. The presented topology can be triggered under positive- and negative-triggering modes at different input terminals. Moreover, the proposed topology provides an advantageous feature of shortening the recovery time required for applying the consecutive triggering signal. The operations of the topology previously presented are reviewed. Then, the proposed circuit is described and analysed in detail. The theoretical analysis is verified through experimental results on a prototype circuit. The improvement on reducing the recovery time is also investigated.

Current-Mode Monostable Multivibrators Using OTRAs

Three nonretriggerable current-mode monostable multivibrators constructed of one operational transresistance amplifier (OTRA) and a few passive elements are presented in this brief. Two of these circuits are operated respectively under positive and negative triggering modes. However, the recovery time cannot be adjusted once the pulsewidth is decided. The third topology, which can work in either triggering mode, features a tunable recovery time. The proposed current-mode monostables are simpler compared to their counterparts composed of operational amplifiers. The circuit operations are described in detail. Experimental results are in good agreement with the theoretical analysis

A new low voltage CMOS differential OTRA for sub-micron technologies

In this study, a new CMOS differential operational transresistance amplifier (OTRA) topology is proposed. This topology can operate with a very low voltage power supply as 1.2 V. In this design, CMOS 0.13 μ m STMicroelectronics technology transistor models are used for the simulations. The designed CMOS OTRA has a transresistance gain (Rm) of 38 660 V/A with a bandwidth ( - 3 dB ) of 29.2 MHz. To demonstrate the performance of the OTRA, designed universal MOS-C filter employing two CMOS differential OTRA are tested with CADENCE simulation program to verify the theoretical results.

Transimpedance Type Fully Integrated Biquadratic Filters Using Operational Transresistance Amplifiers

Operational transresistance amplifier (OTRA) is an inherently suitable active building block for transimpedance type signal processing because of its current input/voltage output nature. It is due ...

Realization of Fully Controllable Negative Inductance with Single Operational Transresistance Amplifier

A grounded negative inductance emulator is proposed with full independent control on both the inductance value and the condition. It uses a single operational transresistance amplifier (OTRA), a capacitor, and five resistors, two of which are for independent control. Experimental results, which confirm the theoretical analysis, are presented.

A Modified CMOS Realization of the Operational Transresistance Amplifier (OTRA)

A modified CMOS realization of the operational transresistance amplifier (OTRA) is presented. A fair comparison with Salama and Soliman OTRA [1] shows that the modified OTRA provides better performance in all parameters. The OTRA is suitable for analog VLSI applications since it does not suffer from constant gain bandwidth product. Hence, it can exhibit wide bandwidth at high gain values. Moreover, an OTRA based variable gain amplifier (VGA) is introduced. A detailed analysis taking the effect of the finite transresistance gain in consideration is provided. Index Terms – CMOS operational transresistance amplifier, analog VLSI applications, variable gain amplifier, wireless communications,

Realization of nth-order voltage transfer function using single operational transresistance amplifier

A new configuration to realize the most general n-th order voltage transfer function is proposed. It employs only one operational transresistance amplifier (OTRA) as the active element. In the synthesis of the transfer function, the RC:−RC decomposition technique is used. To the best of the author's knowledge, this is the first topology to be used in the realization of an n-th order transfer function employing a single OTRA.

Cascadable allpass and notch filters employing single operational transresistance amplifier

A new voltage-mode filter configuration is proposed. The presented topology uses single operational transresistance amplifier (OTRA) and can realize first-order allpass, second-order allpass and notch filtering functions. The proposed circuits are insensitive to parasitic capacitances and resistances due to internally grounded input terminals of OTRA. Low output impedance of the configuration enables the circuits to be cascaded without additional buffers. The theoretical results are verified with PSPICE simulations using a CMOS realization of OTRA. Experimental work is also carried out. The feasibility of the proposed first-order allpass filter is illustrated on the design of a quadrature oscillator.

Novel allpass filter configuration employing single OTRA

A new circuit configuration uses a single operational transresistance amplifier (OTRA) and four passive elements to realize both first- and second-order allpass filters. Owing to internal grounding of the OTRA input terminals, effects of input parasitics are significantly reduced. Applications of the circuit include the realization of the phase equalizer, the quadrature oscillator, and the high-Q bandpass filter for analog signal processing. The performance of the allpass filter is illustrated by circuit-level simulation of a quadrature oscillator with CMOS realization of the OTRA.