CMOS Current Feedback Operational Amplifier Research Articles

Resistorless Chua's diode implementation for chaotic oscillation employing single EXCCCII

A passive resistor-free Chua’s Diode with smooth nonlinearity is introduced using a single Extra X Current Controlled Current Conveyors (EX-CCCII). The proposed Chua’s Diode can generate all fundamental Chua’s chaotic responses like Rossler type attractor, double scroll attractor, and large limit cycle. Chua’s chaotic response can be easily observed in two ways: (i) by tuning the bridging resistor between two capacitors present in a Chua's circuit and (ii) by adjusting the bias current of EX-CCCII present in the proposed Chua’s diode. The proposed Chua’s model is verified with three possible combinations: Chua’s oscillation with a passive inductor, tunable Chua’s oscillation by varying the bias current present in EX-CCCII based negative resistance, and inductor less Chua’s circuit using active inductor based on EX-CCCII. Moreover, the effect of non-idealities present in EXCCCII on negative resistance and dynamical investigation of theproposed Chua’s circuit is described for better understanding. The functionality of the proposed Chua’s circuit is well verified through PSPICE simulation using 0.25 μm TSMC CMOS technology parameters and Current Feedback operational amplifier (CFOA) as IC AD844 based EX-CCCII. In addition to computer simulation, an experimental investigation is also performed by CFOA as IC AD844 to realize EX-CCCII. Finally, a comparison between the existing Chua’s circuit and the proposed one is illustrated for a fair comparison.

A novel Nth-order voltage-mode universal filter based on CMOS CFOA

With the development of integrated circuits, the fully integrated continuous time filter has been focused widely. A Nth-order universal filter based on Current Feedback Operational Amplifier (CFOA) is proposed. Compared with available circuits, the proposed circuit using less components (2n CFOAs, n capacitors, and 3n resistors) can realize the universal filter functions without changing circuit configuration, and the operating frequency of proposed filter circuit is at least 10MHz. All of capacitors in proposed circuit are grounded, this is another benefit from integration point of view. PSPICE simulations have been carried out using 0.18μm CMOS technology, and sensitivity analysis of proposed Nth-order low-pass filter circuit is completed.

A New Design Technique of CMOS Current Feed Back Operational Amplifier (CFOA)

A new design technique employing CMOS Current Feedback Operational Amplifier (CFOA) is presented. This design approach applies CFA OTA as input stage cascaded with class AB cross-coupled buffer stage. The performance parameters of CMOS CFOA such as bandwidth, slew rate, settling time are extensively improved compared with conventional CFOA. These parameters are very important in high frequency applications that use CMOS CFOA as an active building block such as A/D converters, and active filters. Also the DC input offset voltage and harmonic distortion (HD) are very low values compared with the conventional CMOS CFOA are obtained. P-Spice simulation results using 0.35 μm MI-ETEC CMOS process parameters shows considerable improvement over existing CMOS CFOA simulated model. Some of the performance parameters for example are DC gain of 67.2 dB, open-loop gain bandwidth product of 104 MHz, slew rate (SR+) of +91.3 V/μS, THD of -67 dB and DC input offset voltage of -0.2 mV.

Micropower high current-drive class AB CMOS current-feedback operational amplifier

A novel CMOS current-feedback operational amplifier (CFOA) aimed to low-power applications is proposed. The use of a compact class AB implementation allows high current-drive capability and simultaneously very low quiescent power consumption. Measurement results of a fabricated prototype show for an inverting configuration a closed-loop bandwidth of 1 MHz independent of gain setting, and a slew rate of 2V/µs for a load capacitance of 30 pF and a quiescent power consumption of 264µW. Copyright © 2010 John Wiley & Sons, Ltd.

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.

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.

Low-Voltage CMOS Current Feedback Operational Amplifier and Its Application

A novel low-voltage CMOS current feedback operational amplifier (CFOA) is presented. This realization nearly allows rail-to-rail input/output operations. Also, it provides high driving current capabilities. The CFOA operates at supply voltages of ±0.75 V with a total standby current of 304 µA. The circuit exhibits a bandwidth better than 120 MHz and a current drive capability of ±1 mA. An application of the CFOA to realize a new all-pass filter is given. PSpice simulation results using 0.25 µm CMOS technology parameters for the proposed CFOA and its application are given.

Novel CMOS current feedback op-amp realization suitable for high frequency applications

A novel CMOS current feedback operational amplifier (CFOA) is developed for wideband current-mode signal processing. The circuit has a very low input impedance over an exceptionally wide bandwidth and realizes an exact voltage-following action. Simulation results assuming 0.5 /spl mu/m CMOS process shows that the impedance at the current input node is about 2 /spl Omega/ and current and voltage transfer characteristics extend beyond 180 MHz.

Low Voltage Rail to Rail CMOS Current Feedback Operational Amplifier and its Applications for Analog VLSI

This paper presents a new CMOS current feedback operational amplifier (CFOA) with rail to rail swing capability at all terminals. The circuit operates as a class AB for lower power consumption. Besides operating at low supply voltages of ±1.5 V, the proposed CFOA has a standby current of 200 μA. The proposed CFOA circuit is thus a versatile building block for low voltage low power applications. The applications of the CFOA to realize a transconductor/multiplier cell, MOS-C differential integrator, MOS-C bandpass filter and MOS-C oscillator are given. PSpice simulations based on 1.2 μm level three parameters obtained from MOSIS are given.

An offset compensated and high-gain CMOS current-feedback op-amp

This work describes a new CMOS current-feedback operational amplifier (CFOA) with an on-chip continuous-time current-mode input offset voltage compensation circuit. The proposed compensation method is based on a combination of two techniques: the error integration and the current feedback. In addition, this method is irrespective of process and temperature parameters because of its fully symmetrical architecture. HSPICE simulations of the designed CMOS CFOA layout show that the input offset voltage could be reduced to lass than 1 mV, and a gain of around 112 dB and a power consumption of less than 3 mW are achievable.