New details about the frequency behavior of irradiated bipolar operational amplifiers

The frequency behavior of a bipolar operational amplifier (op amp) is always expected to worsen when the device is irradiated. In other words, parameters like the slew rate and the gain-bandwidth product are to decrease after either neutron or gamma tests. However, some neutron and TID tests performed on a large variety of bipolar op amps have shown that the evolution of the frequency behavior is not as simple as it is usually believed. In fact, there is evidence of an increasing influence of the power supply values on the former parameters, which can be extremely important in some devices. Also, the relationship among different frequency parameters has been investigated and, finally, an interesting and scarcely reported phenomenon is depicted. This phenomenon is the appearance of spontaneous oscillations in fed-back op amps, without doubt related to the modification of the gain and phase margins of the device

Load resistor as a worst-case parameter to investigate single-event transients in analog electronic devices

One of the main phenomena that commit the reliability of analog electronic systems working in the outer space is the presence of energetic ions that produce spurious transients after crossing the device. These pulses are transmitted to the network loading the device and can eventually lead to dangerous situations as it has been observed in some spatial missions. This paper shows how the value of the resistor loading the device can affect the shape of the transients

Nanocrystalline tin dioxide thin films as oxidizing gas sensor

Nanocrystalline tin dioxide has been employed to develop two types of sensor devices. Two electrical properties, resistivity and work function, increase with oxidizing gas adsorption. The first leads to the classical thin film resistive sensor. The other property is used to design a switching diode. Both devices show a ligh sensitivity and linearity under proper design and operating parameters. Typival figures are 100% resistance change and 50 mV voltage shift for 50 ppb of NO₂ in air. A theoretical model is proposed to explain the results

An analog cell to detect single event transients in voltage references

A reliable voltage reference is mandatory in mixed-signal systems. However, this family of components can undergo very long single event transients when operating in radiation environments such as space and nuclear facilities due to the impact of heavy ions. The purpose of the present paper is to demonstrate how a simple cell can be used to detect these transients. The cell was implemented with typical {COTS} components and its behavior was verified by {SPICE} simulations and in a laser facility. Different applications of the cell are explored as well

Sistema automático de inducción de transitorios en dispositivos electrónicos por medio de un laser pulsado

En este artículo, se describe un sistema que permite emular por medio de un láser los transitorios que pueden producir los rayos cósmicos en los componentes electrónicos. En particular, el sistema está adaptado para examinar componentes analógicos. Este sistema controla un osciloscopio digital conectado a la salida del dispositivo, que sitúa el láser en un punto específico del circuito integrado, y que almacena el transitorio observado en el dispositivo para realizar un posterior estudio estadístico. Este sistema ha sido utilizado para conocer los transitorios que pueden aparecer en un amplificador operacional (LM124) y un comparador de tensión (LM111)

Radiation effects on CMOS R/2R ladder digital-to-analog converters

The behaviour of CMOS R/2R ladder D/A converters when they are irradiated simultaneously with gamma and neutron radiation is described. The converters suffer an increase of the offset error and a reduction of the linearity because of the malfunction of the internal CMOS switches and the appearance of leakage currents. The effective inputs become "1" whatever the actual input is. No evidence of neutron damage was found

Laser tests on a power operational amplifier

Laser tests on a power operational amplifier were performed to investigate its sensitivity to single event transients. These tests apparently point out to this device being quite insensitive to single event transients so it would become a good candidate to develop power systems to be used in radiation environments

Jules Horowitz reactor project. Exploration tests concerning WIFI modules behaviour under gamma flux

Within the framework of experimental field on technologies developments for research reactors applications, an experimental program dedicated to electronics behaviour under flux has been performed on wireless (WIFI) modules. The interest of using the WIFI modules in an industrial facility is to limit and some cases to work without transmission lines between the experimental equipments in which sensors are embedded and the facility (i.e data acquisition room). The objectives of these tests were to determine the capabilities of WIFI modules to work in Nuclear Environment, to define the limitation due to the dose levels and to propose some adaptations in term of integration. These actions have been carried out on 2009-2010 period, in sharing collaboration between CEA (Commissariat à lEnergie Atomique et aux Energies Alternatives, France), ITN (Nuclear and Technological Institute, Portugal) and UCM (University Complutense of Madrid, Spain). The experimental program on WIFI modules took into account a first phase of data determination of dose levels based on Jules Horowitz Reactor environment. The second phase (performed by UCM and ITN) was dedicated to the selection of modules focused on commercial type (COTS approach). Then, irradiation tests of these modules using a 60Co source and in the RPI reactor have been performed by ITN with UCM. The results obtained are presented and discussed. As conclusion, some recommendations are given

Defining a strategy to perform life-tests with analog devices

Unlike for memory elements inside integrated circuits, scarce life tests have been performed to study single event transients in discrete analog devices. The reason is that life tests require a large amount of samples to be stored for having enough data allowing statistical conclusions and, usually, single event transients are captured by means of oscilloscopes. In this paper, we propose a strategy to carry out life tests in analog voltage comparators by means of digital programmable device that can detect anomalous pulses in the voltage comparator. Besides, the idea on which this kind of tests relies can be extended to be used with other families of analog devices, such as operational amplifiers, voltage references, etc

Statistical Deviations from the Theoretical only-SBU Model to Estimate MCU rates in SRAMs

This paper addresses a well-known problem that occurs when memories are exposed to radiation: the determination if a bitflip is isolated or if it belongs to a multiple event. As it is unusual to know the physical layout of the memory, this paper proposes to evaluate the statistical properties of the sets of corrupted addresses and to compare the results with a mathematical prediction model where all of the events are SBUs. A set of rules easy to implement in common programming languages can be iteratively applied if anomalies are observed, thus yielding a classification of errors quite closer to reality (more than 80% accuracy in our experiments)