Versatile voltage-mode universal biquad filter using the operational amplifier pole

A new multifunction voltage-mode biquad filter topology having three inputs and one output is described. The filter consists of a single operational amplifier (OA), a single capacitor, and two resistors and supports LP, BP, HP, AP and Notch filtering signals from the same topology, without requiring additional components besides being devoid of component matching constraints. The filter uses OA pole and has thereby acquired suitability for extended frequency operation. The natural angular frequency ω₀ and the Q can be separately tuned. The circuit has low sensitivity figures. PSPICE simulation results are employed to verify the circuit performance.     

Large Dynamic Range High Frequency Fully Differential CMOS Transconductance Amplifier

A large dynamic range high frequency fully differential CMOS transconductance amplifier is introduced. It is based on the linear transconductance element proposed in [8] combined with the common-mode feedback circuit in [9]. The original transconductance and common-mode circuits which use two supply voltages are modified for operation under a single power supply. The performance of the complete transconductance amplifier is analysed in details. Simulation results of the whole circuit are also presented, which show that with a single 5 V supply, bandwidth in excess of 300 MHz, THD below 0.7% for a 1 V _pk–pk differential input signal, and dynamic range in excess of 70 dB can be achieved for the fully differential transconductance amplifier.     

High-performance active bandpass filter using current-feedback amplifiers

An accurate current feedback amplifier based high-Q active bandpass filter whose centre frequency is independently variable over a wide frequency range is presented. The basic circuit has the important advantage that access to the Z node of the current-feedback amplifier is not required, as is the case with many existing current-feedback amplifier filter circuits. Additionally, the circuit can be implemented with operational amplifiers, though for high Q the Q? and ω₀? variabilities are 62% better with current-feedback amplifiers than with operational amplifiers. Experimental results are presented which are in good agreement with expected theory.     

Review of microwave distributed superconducting vortex-flow transistor amplifiers

The dynamics of fluxons in the vortex flow transistor (VFT) has been much studied. The fluxon transit time determines the fundamental speed limit of operation. Since fluxons can travel at the velocity of electromagnetic waves in the junction, the VFT has the potential for operating in high frequency systems ( ≈ 100 GHz). However, owing to the low input and output impedance of the VFT, use of the device in a conventional circuit would be quite limited. A distributed amplifier configuration consisting of many VFTs has been proposed to remedy the problems of low impedance levels. However, the realization of such an amplifier circuit at microwave or millimetre wave frequencies depends on obtaining a circuit model. In this paper, microwave superconducting VFT distributed amplifiers using the balanced control technique is reviewed. This kind of amplifier has the advantage that the capacitive feedthrough effect is decreased to a negligible extent. This is the major limiting factor for high frequency applications. The self-field effect which makes the current step inclined is reduced by injecting bias current only around the region of one end of the junction thus obtaining steeper I- V characteristics. With the asymmetric geometry, the slope of the current step is about one hundred times steeper than those obtained with the conventional overlap geometry. Owing to the diamagnetic behaviour of the Josephson junction, a little of the magnetic field induced by the current in the control line is allowed to penetrate the junction. Thus, the transresistance r_m of a VFT is very small. Some methods for maximizing r_m and minimizing the output impedance r₀ also appear in this review. The feasibility of fabricating VFT distributed amplifiers using low-T_c superconducting material has been demonstrated. The power gain of the amplifier can be as high as 15 dB with a flat frequency response.     

Selective Filters and Sinusoidal Oscillators Using CFA Transimpedance Pole

Using a single current feedback amplifier (CFA) device, two new variable frequency sinusoidal RC oscillators are presented. The transadmittance pole of the device (AD-844) has been utilized in the design for generating sine wave signals covering a range of 1 MHz≤f ₀≤31 MHz. Under open-loop conditions, both circuits exhibit resonance characteristics at moderate Q-values (1≤Q≤9). These responses have been experimentally verified with hardware circuit implementation and PSPICE macromodel simulation.     

Voltage/Current-Mode Universal Filter Using FTFN and CFA

A novel configuration for realizing voltage/current-mode (VM/CM) universal filter using a single four terminal floating nullor (FTFN), a single current feedback amplifier (CFA), two capacitors and three resistors is presented. The VM configuration has three inputs and a single output and implements all the five generic filtering functions through the selection of inputs. This topology enjoys cascadability and does not require any additional active element for facilitating the filter realizations. The same circuit in current-mode has a single input and four outputs and realizes LP, HP and two BP responses simultaneously from which AP and Notch can also be realized. This topology uses grounded resistors and capacitors which are ideal for monolithic integration. Both the topologies enjoy orthogonal control of natural frequency (ω₀) and quality factor (Q) by the grounded resistors. The topologies enjoy low active and passive sensitivity figures. Experimental and PSPICE simulation results are also included.     

基于GaN HEMT新型负反馈结构固态宽带功率放大器的研究

The design and fabrication of an ultra-broadband power amplifier based on a Ga N HEMT, which operates in the frequency range from 3 to 8 GHz, is presented in this paper. A TGF2023-02 Ga N HEMT chip from Tri Quint is adopted and modeled. A novel negative feedback structure is applied in the circuit. The measured results show that the amplifier module has a wide range frequency response that is almost consistent with those of simulation at frequencies from 3 to 6.5 GHz. The measured power gain is greater than 7 d B between 3 and 6.5 GHz.The saturated output power is 38.5 d Bm under DC bias of Vds D28 V, Vgs D 3:5 V at the frequency of 5.5 GHz.     

High impedance voltage- and current-mode multifunction filters

This paper presents a voltage- and current-mode multifunction filters based on and employing two four-terminal floating nullors (FTFNs) and a single operation transconductance amplifier (OTA). The high-input impedance voltage-mode configuration can simultaneously realize lowpass (LP), bandpass (BP) and notch filtering functions from the same configuration. The circuit employs two grounded capacitors which suits contemporary IC design techniques. The resonance frequency ω₀ and bandwidth ω₀/Q can be independently tuned while as resonance frequency ω₀ and quality factor Q are orthogonally controllable. The current-mode configuration can simultaneously realize LP and highpass (HP) from which notch filtering signal can also be obtained. The input impedance of the circuit is very low while the output currents are available at very high impedances. The resonance frequency ω₀ and bandwidth ω₀/Q can be orthogonally tuned. The high impedance of both the topologies in the two modes facilitates easy cascading for higher-order filter construction. Passive sensitivity figures are low. PSPICE simulation results are also included.     

AC analysis of an inverter amplifier using minimum-length trapezoidal association of transistors

This paper analyzes the behavior of a single stage MOS amplifier with the substitution of each single transistor of arbitrary W (channel width) and L (channel length) by an equivalent trapezoidal association of MOS transistors (TAT) with minimum length. The goal is to define the most determinant factors in the equivalent TAT selection, taking into consideration, beyond the current matching, also the small-signal behavior. This work shows that the current equivalent association may not be a good alternative when the target single transistor is not part of a bias circuit but part of a gain stage, degrading the circuit low-frequency gain. Moreover, the small signal equivalent association does not modify the bias current, provides the same single transistor circuit gain and has advantages in the frequency response.     

Multi-function biquad using single current differencing transconductance amplifier

An universal multi input single output type multifunction biquad is proposed. The proposed configuration employs only one current differencing transconductance amplifier as the active element, two capacitors and three resistors. The circuit realizes all five filter functions (i.e. Low Pass, High Pass, Band Pass, Notch and All Pass) without changing the circuit topology. The natural frequency ω₀ is independently and electronically tunable. The workability of the proposed multifunction biquad has been verified using SPICE simulation.     

A Reconfigurable Low-Noise Amplifier Using a Tunable Active Inductor for Multistandard Receivers

A reconfigurable low-noise amplifier (LNA) based on a high-value active inductor (AI) is presented in this paper. Instead of using a passive on-chip inductor, a high-value on-chip inductor with a wide tuning range is used in this circuit and results in a decrease in the physical silicon area when compared to a passive inductor-based implementation. The LNA is a common source cascade amplifier with RC feedback. A tunable active inductor is used as the amplifier output load, and for input and output impedance matching, a source follower with an RC network is used to provide a 50 Ω impedance. The amplifier circuit has been designed in 0.18 µm CMOS process and simulated using the Cadence Spectra circuit simulator. The simulation results show a reconfigurable frequency from 0.8 to 2.5 GHz, and tuning of the frequency band is achieved by using a CMOS voltage controlled variable resistor. For a selected 1.5 GHz frequency band, simulation results show S ₂₁ (Gain) of 22 dB, S ₁₁ of ?18 dB, S ₂₂ of ?16 dB, NF of 3.02 dB, and a minimum NF (NFmin) of 1.7 dB. Power dissipation is 19.6 mW using a 1.8 V dc power supply. The total LNA physical silicon area is (200×150) µm².     

High-selectivity grounded capacitor bandpass/low-pass filters using the operational amplifier pole

Using the single-pole model of the operational amplifier (OA) a grounded capacitor network has been analyzed to yield either a bandpass or a low-pass function by adjustment of a single resistor. The bandpass/low-pass filters are suitable for high selectivity applications at extended frequency ranges with the advantage of independent adjustment of pole-frequency, pole-Q factor, and midband/passband transmission gain. The network has low sensitivity to all the circuit parameters. The experimental results are quite in agreement with the analysis.     

Analogue inductor and low-loss capacity multiplier composed of complementary composite follower

A new kind of highQ (quality factor) analogue inductor (L=50H,Q=98.8) and low-loss (loss resistanceR _e ,R _e may approach zero, i. e.Q→∞ capacity multiplier composed of complementary composite follower using field effect and bipolar transistors is proposed. As compared with the analogue inductor and capacity multiplier composed of integrated operational amplifier, the new device has the following features: its circuit is simple, with only one set of supply, more suitable for low frequency large inductor and capacity multiplier, and has complementary temperature characteristics. The working principle of this kind of analogue inductor and capacity multiplier is analysed and the relations betweenQ and ω,Q andr (complementary resistance),R _e andr are established. The design of this kind of device is also discussed and verified experimentally. Moreover the expression for the sensitivity of theQ value of the analogue inductor is derived.     

A novel ±0.8 V high-performance voltage-tunable CDTA with enhanced bandwidth

In this article, we propose a novel high-performance complementary metal oxide semiconductor (CMOS) current differencing transconductance amplifier (CDTA) with a transconductance gain (G_M) that can be linearly tuned by a voltage. By using a high-speed, low-voltage, cascaded current mirror active resistance compensation technique, the proposed CDTA circuit exhibits wide frequency bandwidths, high current tracking precisions as well as large output impedances. The linear-tunable G_M of the CDTA is designed with the use of linear composite metal oxide semiconductor field-effect transistor as basic cells in the circuit. Combining these two approaches, several design concerns are studied, including: impedance characteristic, tracking errors, offset and linearity and noise. The prototype chip with a 0.25 mm² area is fabricated in a GlobalFoundries’0.18 μm CMOS process. The simulated results and measured results with ±0.8 V DC supply voltages are presented, and show extremely wide bandwidths and wide linear tuning range. In addition, a fully differential band-pass filter for a high-speed system is also given as an example to confirm the high performance of the proposed circuit.     

Study of a Ka-Band TE11 Mode Gyrotron Traveling-Wave Amplifier

A Ka-band gyrotron traveling wave (gyro-TWT) amplifier with high power and wide bandwidth operated in the fundamental TE11 circular mode is presented in detail. The stability of the gyro-TWT amplifier using linear and nonlinear theory is analyzed. The distributed loss technique is employed in the interaction circuit which guarantees the amplifier zero-drive stability. The effects of the parameters such as input power, driver frequency, magnetic field on the performance of the gyro-TWT is discussed. The simulation results show that the gain and the bandwidth of the designed Ka-band gyro-TWT are about 60.0 dB and 1.4 GHz at constant drive with an axial velocity spread Dv_z \mathord

Single-input four-output voltage-mode universal filter using single DDCCTA

An electronically tunable universal voltage-mode biquadratic filter with single input and four outputs using one differential difference current conveyor transconductance amplifier (DDCCTA), two resistors and two grounded capacitors is proposed. All the five standard biquadratic filter functions; lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass (AP), can be obtained from the circuit configuration. The LP, BP and HP are simultaneously available without component matching condition. By imposing component choice, the BS and AP responses can also be realized from the same circuit configuration. In addition, the proposed circuit provides an electronic control of its natural angular frequency (ω₀) and quality factor (Q) by adjusting the bias current of the DDCCTA. The simulation results together with the ideal values are also given to demonstrate the performance of the proposed circuit.     

A RGC-based,low-power,CMOS transimpedance amplifier for 10Gb/s optical receivers

ABSTRACT

In this paper, a new low-power transimpedance amplifier (TIA) based on a modified Regulated Cascode (RGC) circuit structure followed by a closed-loop post-amplifier is proposed for 10 Gb/s applications. The main objective of this work is to reduce the power consumption while, the frequency bandwidth of the proposed amplifier is increased considerably. The booster of a conventional RGC is modified by a cascoded transistor and its effect on the performance of the circuit is studied mathematically, which are verified by simulations. The bandwidth extension is occurred due to increasing the gain of the booster amplifier in the RGC stage, which isolates further the input capacitance and results in a reduced input resistance value hence, a higher input pole frequency is obtained in comparison with other conventional RGC structures. On the other hand, by using an active inductive peaking technique, the frequency of the output pole is also increased which results in a further extension of the frequency bandwidth for the proposed circuit. The proposed TIA is simulated using 90 nm CMOS technology parameters, which shows a 50.5 dBΩ transimpedance gain, 7.3 GHz frequency bandwidth and 1.22 µA_rms input referred noise value for only 1 mW of power consumption at 1.2 V supply voltage.     

High-output-impedance current-mode multiphase sinusoidal oscillator employing current differencing transconductance amplifier-based allpass filters

This article presents a multiphase sinusoidal oscillator using current differencing transconductance amplifier (CDTA)-based allpass filters. The oscillation condition and oscillation frequency can be orthogonally controlled. The proposed circuit provides 2n – phase signals (n≥2) that are equally spaced in phase and of equal amplitude. The circuit requires one CDTA, two resistors and one capacitor for each phase and no additional current amplifier. Owing to high-output impedances, the proposed circuit enables easy cascading in current-mode configurations. The effects of the nonidealities of the CDTA-allpass sections were also studied. The results of PSpice simulations are presented, demonstrating their consistency with theoretical assumptions.     

Low sensitivity multifunction active circuits using CFA-based supercapacitor

Some new current feedback amplifier (CFA)-based active Resistance–Capacitance (RC) circuits are presented for the realization of an ideal grounded supercapacitor (Y(s)?=?s ² D) type Frequency Dependent Negative Resistance (FDNR). The D-element is then resonated with additional RC sections to derive multifilter function circuits. The filter function have been tested for continuous resonant frequency (f ₀) tunability in a range of 30?KHz?≤?f ₀?≤?300?KHz with high quality (1?Q?相似文献   

Temperature compensated logarithmic peak detector

A temperature compensated logarithmic amplifier for signal strength indicator or automatic gain control applications is presented. The logarithmic function is realized with a current-feedback operational amplifier with a nonlinear diode feedback. The designed BiCMOS current-feedback operational amplifier utilizes a novel circuit topology which makes possible constant 1 MHz bandwidth amplification with closed loop voltage gains up to 60 dB. The offset current of the current-feedback amplifier is cancelled with an active OTA-C feedback loop. The logarithmically amplified signal is further processed by a peak detector and a temperature compensation circuit. The temperature compensation principle is based on a division of two v _BE:s and it is realized with a current controlled variable current mirror. The logarithmic amplifier is fabricated with a 1.2 micron BiCMOS-process with NPN's f_T of 7 GHz. The power consumption of the circuit is 25 mW with a 4.5 V supply voltage.