Active filter design using operational transconductance amplifiers: A tutorial

Geiger, R.L.; Sánchez-Sinencio, E.

doi:10.1109/mcd.1985.6311946

Cited by 541 publications

(220 citation statements)

References 19 publications

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“…Another technique is given in [13][14][15][16], where the appropriate resistor is replaced by MOSFET-based voltage-controlled resistor. In recently presented voltage differencing-differential input buffered amplifier (VD-DIBA)-based VM APF [17] and in other circuits [18][19][20][21][22][23] the tunability property of the operational transconductance amplifier (OTA) [25] is used to shift the phase response of the circuits. In fact, although the active element VD-DIBA, which belongs to the group of 'voltage differencing' elements [26], is new, it is composed of an OTA and a unity gain differential amplifier (UGDA), an interconnection that is done in [23] separately.…”

Section: Introductionmentioning

confidence: 99%

New resistorless and electronically tunable realization of dual-output VM all-pass filter using VDIBA

Herencsár

Mınaeı

Koton

et al. 2012

Analog Integr Circ Sig Process

113

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In this paper, a new active element called voltage differencing inverting buffered amplifier (VDIBA) is presented. Using single VDIBA and a capacitor, a new resistorless voltage-mode (VM) first-order all-pass filter (APF) is proposed, which provides both inverting and noninverting outputs at the same configuration simultaneously. The pole frequency of the filter can be electronically controlled by means of bias current of the internal transconductance. No component-matching conditions are required and it has low sensitivity. In addition, the parasitic and loading effects are also investigated. By connecting two newly introduced APFs in open loop a novel secondorder APF is proposed. As another application, the proposed VM APF is connected in cascade to a lossy integrator in a closed loop to design a four-phase quadrature oscillator. The theoretical results are verified by SPICE simulations using TSMC 0.18 lm level-7 CMOS process parameters with ±0.9 V supply voltages. Moreover, the behavior of the proposed VM APF was also experimentally measured using commercially available integrated circuit OPA860 by Texas Instruments.Keywords Analog signal processing Á All-pass filter Á Electronically tunable circuit Á Four-phase quadrature oscillator Á Loading effect Á Resistorless filter Á Voltage-mode Á Voltage differencing inverting buffered amplifier (VDIBA)

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Section: Introductionmentioning

confidence: 99%

New resistorless and electronically tunable realization of dual-output VM all-pass filter using VDIBA

Herencsár

Mınaeı

Koton

et al. 2012

Analog Integr Circ Sig Process

113

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“…1b. The CMOS structure utilizing current controlled current conveyor of second generation [3] connected as multiple-output current follower and dual-output OTA section [2,22] is shown in Fig. 2.…”

Section: Z-copy Current-controlled Current Follower Differential Inpumentioning

confidence: 99%

“…We know four types of electronic control in frame of the active element. The first group utilizes controllable transconductance (g m ) [1,2]. The second group deals with controllable intrinsic resistance (R x ) of the current input terminal (mainly in current-mode active elements) [3].…”

Section: Introductionmentioning

confidence: 99%

“…Control of current gain (B ) [4] becomes very popular in recent years mainly [5][6][7][8][9][10][11]. Utilization of the adjustable voltage gain (A) is also very useful in many cases, but complexity of active elements is worse [12] than basic structures utilizing g m or R x control [2,3]. Design of active elements in combination of several (at least two) types of control in frame of one active element is one of today's trends [13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

First–Order Transfer Sections with Reconnection–Less Electronically Reconfigurable High–Pass, All–Pass and Direct Transfer Character

Šotner

Jeřábek

Herencsár

et al. 2016

Journal of Electrical Engineering

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Presented research introduces active filtering circuits which allow change of the transfer type without necessity of reconnection of the input or output terminal that can be very useful for on-chip applications. Our attention is focused on simple first-order filters that allow high-pass response (HP), all-pass response (AP) and also direct transfer (DT) with constant magnitude and phase characteristics between two terminals (input and output) by adjusting of one controllable parameter (current gain B in our case). Useful modification of the well-known current follower transconductance amplifier (CFTA), the so-called Z-copy current-controlled current follower differential input transconductance amplifier (ZC-CCCFDITA) and adjustable current amplifier were utilized in these circuits. Interesting possibilities (crossing between several transfer functions) of presented circuits require different values of B to obtain desired transfer function that is very important for practice and selection of specific way of control. Requirements on value of this continuously controllable gain B differ among presented structures. Theory is supported by simulation and measurement results with behavioral models utilizing commercially available active elements and simulation results with active elements based on CMOS models.

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“…In this paper, two widely used active inductor circuit topologies [2,3] are analyzed using a generalized device circuit model for the transconductance elements. This approach allows us to remove transistor-specific variables such as gate-length and gate-width from the analysis and it enables us to draw a better comparison of the frequency performance of the two topologies.…”

Section: Introductionmentioning

confidence: 99%