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Electronics systems that operate in space or strategic environments can be severely damaged by exposure to ionizing radiation. Space-based systems that utilize linear bipolar integrated circuits are particularly susceptible to radiation-induced damage because of the enhanced sensitivity of these circuits to the low rate of radiation exposure. The phenomenon of enhanced low-dose-rate sensitivity (ELDRS) demonstrates the need for a comprehensive understanding of the mechanisms of total dose effects in linear bipolar circuits. The majority of detailed bipolar total dose studies to date have focused on radiation effects mechanisms at either the process or transistor level. The goal of this text is to provide an overview of total dose mechanisms from the circuit perspective; in particular, the effects of transistor gain degradation on specific linear bipolar circuit parameters and the effects of circuit parameter degradation on select linear bipolar circuit applications.

A front-end read-out application specific integrated circuit (ASIC) for a multichannel pixel X-Ray detector system has been fabricated and tested. The chip provides signal amplification for pixelated compound semiconductors such as Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CZT) with either 1 mm or 200 μm pitch. Both the detector (compound semiconductor) and ASIC are combined to target future research applicable to spectroscopic imaging in high intensity X-Ray biomedical detector systems. The ASIC was fabricated in a 0.35 μm process by Austria Microsystems and consists of 32 channels, where each channel contains a charge-sensitive amplifier, a pulse shaper and two further stages of amplification providing an overall gain of 1 mV per kilo electron volt (keV) for photons within the energy range of 30–120 keV. The preamplifier and shaper circuits are designed for both positive and negative charge collection (electrons and holes) produced by the CdTe or CZT detectors. The ASIC's shaper has been designed with a time constant of 100 ns to allow operation at photon rate events above 1 Million photons per pixel per second. The design and characterization of the readout chip will be discussed in this paper presenting results from both the simulated and the fabricated chip.

In this paper, a single-stage multi-path operational transconductance amplifier (OTA) with fast-settling response for high performance applications is designed. The produced amplifier uses current-shunt technique, double recycling structure, cross-coupled positive feedback configuration and all idle devices in the signal path to enhance transconductance of the conventional folded cascode (FC) amplifier. These transconductance boosting techniques lead to higher DC gain, gain bandwidth (GBW), slew rate and lower settling time compared to the previous FC structures while phase margin is degraded. Simulation results are presented using 90 nm CMOS technology which show 1,800% increment in GBW and a 33.2 dB DC gain improvement in the approximately same power consumption compared to the conventional FC amplifier.

In this work, novel swarm optimization algorithm based on the Artificial Bee Colony (ABC) algorithm called Enhanced Artificial Bee Colony (EABC) algorithm is proposed for the design and optimization of the analog CMOS circuits. The new search strategies adopted improve overall performance of the proposed algorithm. The performance of EABC algorithm is compared with other competitive algorithms such as ABC, GABC (G-best Artificial Bee Colony Algorithm) and MABC (Modified Artificial Bee Colony Algorithm) by designing three CMOS circuits; Two-stage operational amplifier, low-voltage bulk driven OTA and second generation low-voltage current conveyor in 0.13 $\mu$m and 0.09$\mu$m CMOS technologies. The obtained results clearly indicate that the performance of EABC algorithm is better than other mentioned algorithms and it can be an effective approach for the automatic design of the analog CMOS circuits.

For stabilizing the common-mode output voltage of fully differential operational amplifiers, switched-capacitor (SC) type of common-mode feedback (CMFB) is a familiar technique. This is appropriate for implementing high-gain wide-swing low-power op-amps due to its benefits of minimum power consumption, superior linearity across a large amplifier output swing range, and improved feedback loop stability in comparison to continuous-time CMFB. However, the usage of SC-CMFB requires careful attention to some realistic aspects, details of many of which are available in literature. Nonetheless, its adverse effect on the op-amp’s differential-mode gain has not been investigated much. The explanation for this effect is the SC-CMFB-induced equivalent resistive loading, and this is particularly significant in amplifiers like folded cascode which are intended to provide a high gain. This issue of drop in op-amp dc gain because of SC-CMFB, and the consequence on the realization of continuous-time and discrete-time forms of integrators utilizing such amplifiers is the topic of discussion in this paper. Relevant analytical derivations and circuit simulations at the transistor level are provided. A couple of design guidelines and circuit topologies for minimizing the loading-induced gain reduction are also presented.

This paper presents six different meminductor emulator circuits based on operational amplifiers. Five circuits of meminductor emulators have been proposed using two operational amplifiers, one memristor, three resistors and one capacitor, whereas the sixth circuit uses two operational amplifiers, two memristors, one resistor and two capacitors. All circuits of the proposed meminductor emulators are very simple over most of the realizations of meminductor emulators in the literature. The behaviors of meminductor emulators are satisfactory over a wide range of frequencies. The proposed configurations of meminductor emulators have been simulated by the LTspice tool. The SPICE models of both operational amplifier (AD711) and memristor have been used for simulation. The workability of the proposed meminductor emulators has also been verified using the basic and well-known structure of operational amplifier. In addition, the pinched hysteresis loop obtained by the simulation results of meminductor emulator has been achieved by the experimental results as well. Chaotic oscillator has been designed using the proposed meminductor emulator to prove the worthiness of the design.

An operational amplifier (OPAMP) for portable devices with dual supply voltage is presented in this work. The design is realized with a 600mV supply for the core design and a 1.8V supply for the biasing circuit to improve input common mode range (ICMR), gain, and common mode rejection ratio (CMRR). The designed amplifier is implemented with dynamic threshold voltage MOSFET (DTMOS) transistors to decrease power consumption and increase the performance of the design. The power consumption of the core design is obtained as 2$\mu$W while the biasing circuitry consumes 7.38$\mu$W. The application of different supply voltages has greatly increased the gain of the circuit, where the circuit exhibits 100.2dB DC gain and 3.41MHz gain bandwidth product (GBW). CMRR of the designed circuit is 84.22dB. The simulations are performed in Cadence environment with 0.18$\mu$m CMOS technology.

A plug-and-play kit that can be used as a teaching aid in high school has been designed, which mimics the behavior of recently discovered TiO₂ based memristor. The circuit uses easily available off-the-shelf components to emulate a memristor. SPICE simulations and lab results are shown to validate the proposed circuit.

Electronics systems that operate in space or strategic environments can be severely damaged by exposure to ionizing radiation. Space-based systems that utilize linear bipolar integrated circuits are particularly susceptible to radiation-induced damage because of the enhanced sensitivity of these circuits to the low rate of radiation exposure. The phenomenon of enhanced low-dose-rate sensitivity (ELDRS) demonstrates the need for a comprehensive understanding of the mechanisms of total dose effects in linear bipolar circuits. The majority of detailed bipolar total dose studies to date have focused on radiation effects mechanisms at either the process or transistor level. The goal of this text is to provide an overview of total dose mechanisms from the circuit perspective; in particular, the effects of transistor gain degradation on specific linear bipolar circuit parameters and the effects of circuit parameter degradation on select linear bipolar circuit applications.