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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.

• 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

• HIGH-SPEED OUTPUT STAGES OF OPERATIONAL AMPLIFIERS WITH DIFFERENCING CIRCUIT CORRECTION OF TRANSITION PROCESS

  А.А. Zhuk

  2024-11-10

  Abstract ▼

  The development and design of gallium arsenide (GaAs) analogue functional units in modern microelectronics
  (operational amplifiers, output stages, etc.) is at the initial stage of development. This is
  because GaAs wide-gap semiconductors are currently positioned primarily for high-current and ultrahigh-
  frequency electronics (e.g., power supplies, power amplifiers, etc.). To create micro-power analogue
  component base operating under severe operating conditions, for example, under high temperatures
  (+300...+350°C) and radiation, it is necessary to develop special GaAs circuit solutions that take into
  account the parameters and limitations of the corresponding technological processes. A family of output
  stages protected by 5 patents of the Russian Federation for various modifications of GaAs micro-power
  operational amplifiers is proposed, which can be realised on the combined GaAs technological process
  allowing to create n-channel field-effect transistors with control p-n junction and GaAs bipolar p-n-p
  transistors. The considered OS circuits differ from each other by the values of input and output resistances,
  static current consumption, circuitry of static mode establishment circuits, frequency range, maximum
  amplitudes of positive and negative output voltage, etc. The results of comparative computer modeling of
  the static mode, amplitude and amplitude-frequency characteristics of the OS in LTspice simulation software
  are given. The proposed circuit solutions are recommended for application in GaAs micro-power
  operational amplifiers of new generation, as well as for use in various GaAs analog microelectronic devices,
  including those operating under severe operating conditions: exposure to penetrating radiation and
  low temperatures. At small-scale production of the proposed output stages it is recommended to perform
  them on GaAs technological process mastered by Minsk Scientific Research Institute of Radio Materials
  (JSC ‘MNIIRM’, Minsk, Republic of Belarus), which allows the operation of the proposed circuits at high
  temperatures (up to +300...+350 oC), as well as under the influence of penetrating radiation with absorbed
  dose of gamma-quanta (up to 1 Mrad) and neutron flux (up to 1013 n/cm2).

• HIGH-SPEED OUTPUT STAGES OF OPERATIONAL AMPLIFIERS WITH DIFFERENCING CIRCUIT CORRECTION OF TRANSITION PROCESS

  А.А. Zhuk

  2023-12-11

  Abstract ▼

  For the first time, a circuit design solution with an increased maximum output voltage rise
  (decay) rate of a family of classic AB class output stages, which are the basis of many integrated
  circuits of operational amplifiers (544UD1, 153UD4, A741, etc.), is presented. For this purpose,
  special elements of transient process in the large signal mode are introduced into the basic circuits
  of the output stages. The circuitry of this class is implemented on both bipolar (BJT) and
  CMOS transistors. The results of computer simulation in the LTspice XVII simulation software
  show that, in comparison with classical circuits, due to the introduction of an additional differentiating
  capacitor and an input emitter repeater, the maximum rate of decay in the output voltage of
  the output stages increases by more than 500 times. At the same time, the considered output stage
  circuits provide output voltages with maximum amplitude from - 8.5 V to + 10 V with a relatively
  low load resistance (up to 2 kOhm) and supply voltages of ± 10 V. It is shown that for small-scale
  production of the proposed output stages, their execution on basic matrix crystals MH2XA031 is
  recommended (OJSC “Integral”, Minsk, Belarus), which will reduce the cost-effectiveness of
  manufacturing microelectronic products. The basic matrix crystal MH2XA031 based on the 3CBiT process technology allows the proposed schemes to operate at low temperatures (up to - 197 °C),
  as well as under the influence of penetrating radiation with an absorbed dose of gamma quanta
  (up to 1 Mrad) and a neutron flux (up to 1013 n/cm2).