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• CIRCUIT DESIGN METHOD FOR IMPROVING LARGE-SIGNAL SPEED OF CLASSICAL OUTPUT STAGES OF OPERATIONAL AMPLIFIERS USING BJT (CMOS, JFET OR SIGE) TRANSISTORS

  А.А. Zhuk , А.I. Gavlitskiy , N.N. Prokopenko

  265-277

  2026-07-07

  Abstract ▼

  A significant drawback of classical output stages of microelectronic operational amplifiers, which today are implemented based on BJTs (bipolar junction transistors), CMOS (complementary metal-oxide-semiconductor transistors), or JFETs (junction field-effect transistors), including when these technologies are used together, is that they exhibit a relatively low output voltage slew rate under the influence of large-amplitude pulsed input signals. This undesirable effect is mainly caused by the presence of parasitic capacitances inherent in the reference current source circuits employed and in their output transistors. This paper discusses an original and effective circuit design technique that provides forced recharging of parasitic capacitances, which is used in output stages implemented in numerous patents of the world’s leading microelectronic companies. The introduction of a special differentiating transient correction circuit into the original schematics, as well as various options for its practical implementation, are considered for the first time. The circuitry of such output stages is protected by a patent of the Russian Federation. Four different modifications of buffer amplifiers have been developed and investigated, which are intended for use in modern technological processes implemented with silicon BJT or CMOS transistors, as well as with gallium arsenide n-JFET and p-n-p bipolar transistors. Examples of computer simulation of DC operating modes, as well as transient processes, are presented, which clearly demonstrate a significant increase in the maximum output voltage slew rate (by more than one to three orders of magnitude). The proposed advanced circuit solutions for GaAs transistors are recommended for practical application in microelectronic devices designed for operation under elevated temperature conditions.

• EARLY DETECTION OF MANUFACTURING DEFECTS IN SMALL-SCALE PRODUCTION USING NEURO-FUZZY SYSTEMS

  S.А. Prokopenko , А. V. Bobryakov

  2026-02-27

  Abstract ▼

  Problem Statement: The increasing demand for higher quality products in small-scale production and the complexity associated with the early detection of manufacturing defects necessitate the development of innovative approaches to predict and control defects at the early stages of manufacturing complex technical objects. Traditional methods applied in mass production settings are unsuitable for small-scale manufacturing due to the high variability of technological processes and the insufficient data required for conventional statistical analyses. The objective of this study is to reduce the incidence of manufacturing defects by identifying deviations at the preparatory stages of production. The proposed solution involves employing neuro-fuzzy systems capable of adaptively forecasting defects based on historical production data. Methods: To address the early detection of manufacturing defects, neuro-fuzzy components based on the fuzzy neuron proposed by Kwan–Cai were employed, integrating expert knowledge with production data. The system includes a training and fine-tuning subsystem consisting of modules for data preparation, validation and normalization, fuzzification of data, and calculation of forecasting errors. Temporal neuro-fuzzy Petri nets were used as structural forecasting elements, enabling the consideration of temporal aspects and uncertainties inherent in manufacturing processes. Novelty: The novel aspects of this research include the utilization of temporal neuro-fuzzy Petri nets and neuro-fuzzy components based on the Kwan–Cai fuzzy neuron, enabling the early detection of defects and the implementation of proactive measures. Another innovative aspect is the approach for integrating neuro-fuzzy methods into existing production management systems. Results: The implementation of the proposed methods resulted in a 15% reduction in manufacturing defects through early identification of deviations and the timely adoption of corrective actions. Developed software tools provide operational analysis of production situations and defect forecasting in near real-time. Practical Significance: The presented solution has been realized as specialized software integrated into existing production systems. It improves the effectiveness of quality management, reduces the costs associated with defect correction, and can be adapted to various small-scale production environments, significantly enhancing their operational performance.

• DISCRETE-ANALOGUE FILTER OF THE SECOND ORDER ON SWITCHED CAPACITORS WITH TUNING OF POLE FREQUENCY BY DIGITAL POTENTIOMETER

  D.Y. Denisenko , N.N. Prokopenko , Y.I. Ivanov , D.V. Kuznetsov

  179-189

  2025-11-10

  Abstract ▼

  A discrete-analogue filter of the second order on two frequency-switching capacitors is developed and investigated. The proposed circuit contains two inputs (In_LPF_HPF, In_BPF_NPF) and four outputs (Out_LPF, Out_BPF, Out_HPF, Out_NPF). The filter type (numerator of the transfer function) is determined by connecting a signal source to the corresponding input of the circuit and taking a signal from the corresponding output. The pole attenuation depends on the resistance of a single resistor R5, which does not affect the other parameters. Therefore, the pole attenuation can be tuned using this resistor. To set the passband gain at a given level, it is appropriate to use resistor R1 in the LPF and HPF, and resistor R2 for the BPF and NPF. Changing these resistors will not cause changes in other parameters of the filter circuit. It is established that the pole frequency depends on the resistance of the resistor R8 or digital potentiometer Kdp (Kf), the transmission coefficient of which can be changed by changing the binary digital code Kf, fed to its control inputs, and the other parameters of the filter link do not depend on them, so by changing the resistance of this resistor or the transmission coefficient of the digital potentiometer the pole frequency can be tuned in a wide range while preserving other parameters. Computer modelling of the investigated discrete-analogue filter is performed in Micro-Cap environment. The sequences of pulses controlling electronic keys are given. Graphs of output voltages at the circuit outputs (Out_LPF, Out_BPF, Out_HPF, Out_NPF) are shown. The application of a digital potentiometer in the filter circuit is extremely promising in the construction of adaptive signal processing systems.

• SIGE BICMOS OUTPUT STAGES OF HIGH-TEMPERATURE OPERATIONAL AMPLIFIERS

  А.А. Zhuk , D. V. Kleimenkin , N.N. Prokopenko

  143-159

  2025-11-10

  Abstract ▼

  Development and design of silicon-germanium (SiGe) analog functional units (operational amplifiers, output stages, etc.) is one of the urgent tasks in modern microelectronics. The use of the combined technological process of SiGe BiCMOS makes it possible to combine in a single integrated circuit the advantages of complementary CMOS triansistors (low power consumption and high integration density) and bipolar heterojunction transistors (HBT) n-p-n type (the ability to operate at high frequencies, low power consumption and, as a result, low intrinsic heat dissipation, high gain, high performance, increased reliability, relatively low cost). To create a micro-power analog component base operating at high temperatures (up to + 250 degrees Celsius), it is necessary to develop special SiGe BiCMOS circuit solutions that take into account the process limitations on the use of certain types of transistors. Four modifications of buffer amplifiers for application as output stages of operational amplifiers, which are oriented to SiGe BiCMOS technological process, are investigated. A program for cataloging and visualization of the considered circuits is developed, which differ from each other by the values of input and output resistances, static current consumption, circuitry of static mode establishment circuits, maximum amplitudes of positive and negative output voltages, etc. Examples of computer simulation of static modes and amplitude characteristics in the Cadence electronics and microelectronics design environment at two temperatures of + 27 and + 250 degrees Celsius are given. The proposed circuit design solutions are recommended for practical use in microelectronic devices operating at elevated temperatures

• FEATURES OF THE CIRCUITRY OF OPERATIONAL AMPLIFIERS BASED ON COMPLEMENTARY FIELD-EFFECT TRANSISTORS WITH A CONTROL PN-JUNCTION

  N.N. Prokopenko, V.Е. Chumakov, А.V. Bugakova, А.Е. Titov

  126-135

  2025-08-01

  Abstract ▼

  The systematic component of the offset voltage (Voff) of two-stage BJT and CMOS operational
  amplifiers (Op-Amps) with classical architecture significantly depends on the numerical
  values (difference from unity) of the current transfer coefficient (Ki≈1) of the current mirrors (CM)
  used. This parameter of CM is also influenced by the Earley stress of their dominant active components.
  Current JFET mirrors are today a weak link in modern JFET analog circuitry and they
  are impractical to use in the structure of JFET Op-Amps. The article posed and solved the problem
  of the conditions for the elimination of CM in an Op-Amps based on field-effect transistors
  with a control pn-junction for the case when it is necessary to obtain a small Voff. Variants of practical
  circuits of input (InS) and intermediate (IntS) stages of microelectronic operational amplifiers
  based on complementary field-effect transistors with a control pn-junction (CJFET) are proposed.
  Their main feature is the absence of a current mirror, which, when implemented on a
  CJFET, negatively affects the main parameters of the Op-Amps in terms of the systematic component
  of the offset voltage, the attenuation coefficients of the input common-mode signal, and the
  suppression of noise on the power buses. In this regard, InSs and IntSs circuits are promising,
  which do not use this CJFET functional unit. The circuits of Op-Amps based on the developed InSs
  with an open gain of more than 80 dB and a systematic component of the offset voltage within 300
  μV with low current consumption in a static mode are presented. The relevance of the performed
  studies lies in the need to develop the theory of designing high-precision JFET and CJFET IPmodules
  for use in structures of low-noise analog interfaces of sensors of various physical quantities,
  including those operating in severe operating conditions (exposure to low temperatures and
  radiation) The proposed circuits can be implemented on wide-gap semiconductors (SiC JFET,
  GaN JFET or GaAs JFET).

• CIRCUIT FEATURES OF HIGH-TEMPERATURE ANALOG MICROCIRCUITS ON GAN AND GAAS TRANSISTORS

  А.V. Bugakova, N.N. Prokopenko, D.V. Kleimenkin, О.V. Dvornikov, V.А. Tchekhovski

  2024-05-28

  Abstract ▼

  High-temperature integrated circuits, which remain operational at temperatures above 150°C, are
  required in many areas of industry: aerospace, aviation and automotive instrumentation, the petrochemical
  industry, electric power, and military electronics. Currently, foreign enterprises are mass-producing
  several high-temperature analog and analog-to-digital microcircuits based on silicon CMOS SOI structures
  – ADS1278-HT, ADS1282-HT, ADS8320-HT, INA129-HT, INA333-HT, OPA2333-HT, etc. Hightemperature
  silicon operational amplifiers and ADCs have also been developed in the Russian Federation.
  However, the maximum operating temperature of such products does not exceed 200°C due to the limitations
  of silicon technologies. For this reason, wide-bandgap semiconductors such as silicon carbide (SiC),
  gallium nitride (GaN) and gallium arsenide (GaAs) are most often considered as semiconductors intended
  for high-temperature microcircuits, which provide a number of characteristics necessary for hightemperature
  applications: wide bandgap, high carrier saturation velocity and low concentration of intrinsic
  charge carriers. An overview of the problems of developing high-temperature analog microcircuits
  based on GaN and GaAs transistors is presented. The features of the current-voltage characteristics of
  GaN and GaAs field-effect transistors operating in depletion and enhancement modes, electrical circuits
  of typical analog devices (charge-sensitive and operational amplifiers, comparators, current followers)
  and logical gates are considered. It is concluded that it is advisable to carry out the circuit synthesis of
  GaAs analog microcircuits using field-effect transistors with an n-type channel operating in depletion
  mode and p-n-p heterostructure bipolar transistors. Examples of such schemes are given. The relevance of
  the above research is related to the problems of import substitution of microcircuits based on widebandgap
  semiconductors (GaN, GaAs), providing a wide range of operating temperatures (over +150°C).

• COMPARATIVE ANALYSIS OF TWO- AND SINGLE-STAGE BJT-JFET OPERATIONAL AMPLIFIERS

  О.V. Dvornikov, V. А. Tchekhovski, А.V. Kunts, N.N. Prokopenko, V.E. Chumakov

  2023-10-23

  Abstract ▼

  Operational amplifiers with different number of amplifying stages realized on complementary
  bipolar transistors and input field-effect transistors, with control p-n junction are considered.
  For the elements of the master slice array MH2XA031 the original electrical schematics of three
  amplifier variants (OAmp11.3, OAmp12, OAmp14) containing the same static mode bias block
  and output stage are given. The OApm11.3 circuit contains an input differential stage in the form
  of a " folded" cascode on p-JFETs and an intermediate amplifier stage on bipolar transistors. The
  operational amplifier OAmp12 includes an input dual source-repeater on p-JFETs and an " folded"
  cascode on complementary bipolar transistors. The OAmp14 circuit is realized on the basis of
  dual source repeaters on p-JFETs and a high-precision voltage-to-current converter on complementary
  bipolar transistors in the intermediate stages. The presented electrical circuits are characterized
  by low zero offset voltage, relatively high voltage gain and can be used for application in special and dual-purpose equipment. When designing the Op-Amp circuits on the master slice array
  MH2XA031 the search for a compromise combination of input current, noise level and voltage gain
  was carried out, and special attention was paid to the choice of the operating mode of the input
  JFETs. Single amplifier stage circuits, which typically provide lower noise, simple frequency correction,
  and larger bandwidth, were investigated. For an adequate comparison of the developed amplifiers
  the modeling of their static and dynamic parameters at the same operating mode of identical
  circuit elements has been performed, which allowed to formulate recommendations on circuit synthesis
  of operational amplifiers depending on the required combination of parameters. When optimizing
  the operating mode of the transistors of the " folded" cascode with input JFETs, the recommendations
  consisting in the necessity to increase the steepness of the input JFET transistors and the voltage
  drop across the emitter resistors of the reference current sources were used.

• CIRCUITRY METHODS FOR INCREASING THE SPEED OF OPERATIONAL AMPLIFIERS BASED ON A "FOLDED" CASCODE

  N.N. Prokopenko, D.V. Kleimenkin, М.А. Sergeenko

  2023-06-07

  Abstract ▼

  Three circuit techniques are proposed that provide (with simultaneous use) an increase by
  more than two orders of magnitude of the maximum output voltage slew rate (SR) of microelectronic
  operational amplifiers (op-amps) based on bipolar transistors with a classical architecture,
  designed to operate in automatic control systems, radio engineering and communications, for
  example, as drivers for ultra-high-speed analog-to-digital converters (EVIOAS150, EVIOAS350,
  AD9208, AD9691, 1273PV14, etc.). The considered op-amps contain a cascode input stage with a
  non-linear correction of the pass-through characteristic and a tracking circuit that increases the
  attenuation coefficient of the input common-mode signals and the noise suppression coefficient on
  the power buses, as well as an intermediate stage based on a “folded” cascode. The use of a
  "folded" cascode makes it possible to increase the efficiency of using power supply voltages, as
  well as to increase the unity gain frequency of the corrected op-amp. However, such an intermediate
  stage is an essential non-linear link that limits the maximum output currents that recharge the
  op-amp correction capacitor. The results of computer simulation of two modifications of the
  AmpSR1, AmpSR2 op amps, which differ from each other in the structure of a nonlinear parallel
  channel, which eliminates the dynamic overload of a "folded" cascode, are presented. The relevance
  of the research performed is related to the problems of import substitution in the class of
  high-speed op-amps and the lack of new and promising ideas for increasing the SR of the op-amp
  based on the simultaneous use of non-linear and differentiating transient correction circuits in the
  large signal mode among analog circuit designers. The considered circuit techniques are also
  effective when using CMOS technological processes.

• A FAMILY OF SECOND-ORDER ACTIVE RC FILTERS (LPF, HPF, BPF) WITH INDEPENDENT ADJUSTMENT OF THE MAIN PARAMETERS

  D.Y. Denisenko, Y.I. Ivanov, N.N. Prokopenko

  2023-02-27

  Abstract ▼

  A bank of circuit design solutions for active RC filters of the second order is considered - a
  low-pass filter, a high-pass filter and band-pass filters, in which independent tuning of the main
  parameters - the pole frequency, the quality factor of the pole and the transmission coefficient is
  provided. From these positions, the requirements for three special transfer functions of a multipole
  frequency-setting RC circuit, which contains two resistors and two capacitors, are formulated.
  By choosing the coefficients of the numerator of the first transfer function, the type of the required
  filter (LPF, HPF, BPF) is implemented. The coefficients of the second transfer function are chosen
  so that they affect only the frequency of the pole. It should be noted that, depending on the set of
  coefficients of the transfer function numerator polynomial, the developed circuits have the property
  of lowering the pole frequency or increasing the pole frequency. In this case, the choice of parameters
  of the third transfer function provides the necessary attenuation of the pole. Using the
  The introduction describes a generalized architecture of second-order active RC filters, which
  allows implementing an algorithm for step-by-step tuning of the main parameters and can be used
  as the basis for the synthesis of many other modifications of active RC filters. For correct independent
  adjustment, the following sequence must be observed: the frequency of the pole, the second
  stage is the adjustment of the quality factor of the pole, and the third stage is the scaling
  factor. The stages of synthesis of this class of active RC filters are considered, the coefficients of
  the transfer functions of the presented circuits of 12 band-pass filters, a high-pass filter and a lowpass
  filter, confirmed by 14 patents of the Russian Federation, are given.