-
[show abstract]
[hide abstract]
ABSTRACT: The influence of a load resistor on the shape of the single event transients was investigated in the LM124 operational amplifier by means of laser tests. These experiments indicated that, as a general rule, load resistors modify the size of the transients. SPICE simulations helped to understand the reasons of this behavior and showed that the distortion is related to the necessity of providing or absorbing current from the load resistor, which forces the amplifier to modify its operation point. Finally, load effects were successfully used to explain the distortion of single event transients in typical feed-back networks and the results were used to explain experimental data reported elsewhere.
IEEE Transactions on Nuclear Science 03/2010; · 1.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Some samples of the ISO122 and the ISO124, capacitor-based isolation amplifiers from Texas Instruments, were irradiated in a neutron & gamma environment in order to investigate their tolerance to the total radiation dose. After the experimental data, the most sensitive parameters were the offset voltages, transmission gain and the typical output error. In any case, devices are still operative after receiving 2.2middot10<sup>13</sup> 1-MeV nmiddotcm<sup>-2</sup> & 235 Gy(Si).
Radiation and Its Effects on Components and Systems, 2007. RADECS 2007. 9th European Conference on; 10/2007
-
[show abstract]
[hide abstract]
ABSTRACT: Power operational amplifiers were irradiated in a mixed neutron and gamma radiation environment. These experiments showed that the degradation of the power operational amplifiers shares a great deal of characteristics with that of the low signal devices (e.g., shift of the input offset voltage, increase of the input bias currents, and degradation of the frequency behavior). However, other phenomena were observed without equivalence in the family (linear dependence of the inverse of the quiescent current on the neutron fluence, more significant degradation of the negative output current and collapse of the primary operational amplifiers). These phenomena were explained from the special characteristics of the output stage, optimized to provide a current of several amperes. Finally, even though power devices are especially sensitive to radiation damage, some of the tested devices are suitable for radiation levels on the order of 5 ldr 10<sup>13</sup> - 10<sup>14</sup> n ldr cm<sup>-2</sup> in case the whole electronic system, in which the device is integrated, is carefully designed.
IEEE Transactions on Nuclear Science 09/2007; · 1.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Radiation tests have shown the existence of inactivity windows in analog switches. It means that the devices lose their ability to switch between ON and OFF states if the total radiation dose is placed between two characteristic values. Once the total radiation dose goes beyond the top value of the window, the switching ability reappears. A physical mechanism based on the evolution of the threshold voltage of irradiated NMOS transistors is proposed in this paper. Finally, consequences of inactivity windows in the conception of radiation tests are discussed
IEEE Transactions on Nuclear Science 09/2006; · 1.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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 devices
IEEE Transactions on Nuclear Science 09/2006; · 1.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Discrete bipolar operational amplifiers were irradiated with neutrons in order to study the evolution of the short circuit currents. Also, this paper explores the effect of the reduction of this current in devices based on operational amplifiers.
IEEE Transactions on Nuclear Science 11/2005; · 1.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Radiation tests have shown the existence of inactivity windows in analog switches. It means that the devices lose their ability to switch between ON & OFF states if the total radiation dose is placed between two characteristics values. Oddly, once the total radiation dose goes beyond the top value of the window, the switching ability reappears. A physical mechanism based on the evolution of the threshold voltage of irradiated NMOS transistors is proposed in this paper. Finally, consequences of inactivity windows in the conception of radiation tests are discussed. Besides, not only were observed the typical leakage currents but an unexpected dependence on the logic input value was found as well. A theory to explain this effect is also developed.
Radiation and Its Effects on Components and Systems, 2005. RADECS 2005. 8th European Conference on; 10/2005
-
[show abstract]
[hide abstract]
ABSTRACT: The frequency behaviour of irradiated bipolar op amps 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 behaviour 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 values of 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 unknown phenomenon is finally depicted. This phenomenon is the appearance of spontaneous oscillations in fed-back op amps, without doubt related to a modification of the gain and phase margins of the devices.
Radiation and Its Effects on Components and Systems, 2005. RADECS 2005. 8th European Conference on; 10/2005
-
[show abstract]
[hide abstract]
ABSTRACT: This paper describes the evolution of different commercial microprocessor supervisory circuits under neutron and gamma radiation. After the irradiation, the tested devices showed some interesting changes: an increase of supply current and the period of watchdog timer. It was also observed that threshold voltage hysteresis and the shift of TTL trigger level appeared in some devices.
Radiation Effects Data Workshop, 2005. IEEE; 08/2005
-
[show abstract]
[hide abstract]
ABSTRACT: XFET references make up a new kind of voltage references different from the popular band-gap or buried Zener devices. These references are built by means of a reference cell consisting of a couple of p-channel junction field effect transistors with different pinch-off voltage values and an operational amplifier for the purpose of improving the output characteristics of the whole device. An irradiation in a mixed gamma and neutron environment was performed at the Portuguese Research Reactor for a complete characterization of the devices. Some of the parameters were measured during the irradiation while the rest of them were obtained once the samples were removed from the neutron facility. Experimental results show that some references belonging to this class are interesting candidates for a design of radiation-tolerant electronic systems based on COTS devices.
Radiation Effects Data Workshop, 2005. IEEE; 08/2005
-
[show abstract]
[hide abstract]
ABSTRACT: This paper is devoted to the description of the evolution of different commercial microprocessor supervisory circuits under neutron radiation. After the irradiation, the tested devices showed some interesting changes: the increase of supply current and the duty cycles for watchdog timer. It was also observed that in some devices existed threshold voltage hysteresis and their trigger level was not in the usual TTL range of 0-5V.
Electron Devices, 2005 Spanish Conference on; 03/2005
-
[show abstract]
[hide abstract]
ABSTRACT: Radiation tests on CMOS analog switches were carried out in order to select the most tolerant device for future use in the cryogenic system of the CERN large hadron collider. After irradiation, the devices showed some interesting changes related to the power supplies: an increase in the lowest supply voltage capable of biasing correctly the devices; some devices cannot work with TTL logic levels. In addition, hysteresis phenomena appear.
Radiation Effects Data Workshop, 2004 IEEE; 08/2004
-
[show abstract]
[hide abstract]
ABSTRACT: Tests on instrumentation amplifiers exposed to neutron radiation have been done. The tested devices were commercial instrumentation amplifiers or designed with rad-tol commercial operational amplifiers. The results show changes in frequency behavior, gain, offset voltage, output saturation voltages, and quiescent current. The radiation tolerance is bigger in amplifiers with JFET input stage or with large frequency bandwidth and is smaller if the amplifier has been designed for reducing the power consumption. The IAs built with OPAMPs have a higher tolerance than the commercial ones, but they have disadvantages: high temperature influence, low CMRR, etc.
IEEE Transactions on Nuclear Science 01/2004; · 1.45 Impact Factor
-
Radiation and Its Effects on Components and Systems, 2003. RADECS 2003. Proceedings of the 7th European Conference on; 10/2003
-
Radiation and Its Effects on Components and Systems, 2003. RADECS 2003. Proceedings of the 7th European Conference on; 10/2003
-
[show abstract]
[hide abstract]
ABSTRACT: The field electronics for the LHC cryogenic system will be subjected to neutron and gamma radiation. Its baseline design is based on COTS and a DMILL ASIC. The COTS include anti-fuse FPGA's, WorldFIP fieldbus interface and discrete integrated circuits.
-
J.A. Agapito,
F M Cardeira,
J Casas-Cubillos,
A C Duarte,
A Fernandes,
F.J. Franco,
M J Gil,
P Gomes,
I C Gonçalves,
A Hernández-Cachero,
U Jordung,
M A Martin,
J G Marques,
A Paz,
A J G Ramalho,
M A Rodríguez-Ruiz,
J.P. Santos
-
[show abstract]
[hide abstract]
ABSTRACT: Resumen Se ha construido un sistema de medida automático basado en sensores resistivos para la detección de vapores procedentes de líquidos. La medida se realiza mediante un multímetro digital provisto de una interfaz GPIB para su conexión a un PC. El control se lleva a cabo con tarjetas digitales y ana-lógicas de aplicación específica. Con este sistema se han clasificado tanto líquidos, tales como vinos y diferentes concentraciones de alcohol, como mezclas de gases. Los datos obtenidos son procesados por una ANN (Red neuronal artificial) que permite la clasifica-ción e identificación de los líquidos y gases medi-dos. Palabras Clave: sensores de estado sólido, detec-ción de vapores, redes neuronales, tarjetas de adqui-sición de datos.
-
[show abstract]
[hide abstract]
ABSTRACT: Some samples of the ISO122 and the ISO124, capacitor-based isolation amplifiers from Texas Instruments, were irradiated in a neutron & gamma environment in order to investigate their tolerance to the total radiation dose. After the experimental data, the most sensitive parameters were the offset voltages, transmission gain and the typical output error. In any case, devices are still operative after receiving 2.2·10 13 1-MeV n·cm −2 & 235 Gy(Si). Index Terms—Accumulated radiation damage, isolation am-plifiers, neutron damage, operational amplifiers, pulse-width modulation (PWM), total ionising dose.
-
[show abstract]
[hide abstract]
ABSTRACT: The cryogenic system of the LHC will use Pt-100 sensors to measure temperatures between 40-300 K and isolation de-vices will be used. The selected commercial components must be rad-tolerant since a total radiation dose of 5·10 12 n/cm 2 & 100 Gy is expected during ten years of the LHC lifetime. Neutron tests in this family of devices were performed and the results are shown in this paper.
