W.R. Crain

Observation of single event upsets in analog microcircuits

Selected analog devices were tested for heavy-ion-induced single event upset (SEU). The results of these tests are presented, likely upset mechanisms are discussed, and standards for the characterization of analog upsets are suggested. The OP-15 operational amplifier, which was found to be susceptible to SEU in the laboratory, has also experienced upset in space. Possible strategies for mitigating the occurrence of analog SEUs in space are also discussed. >

Correlation of picosecond laser-induced latchup and energetic particle-induced latchup in CMOS test structures

We show that the thresholds for picosecond (psec) laser pulse-induced latchup and energetic particle-induced latchup are well correlated over a range of bulk CMOS test structures designed to be susceptible to latchup. The spatial length of the latchup-sensitive node of the test structures covers a range of values that commonly occur in bulk CMOS devices. The accuracy of this correlation implies that laser-induced latchup can be used for hardness assurance and, under the proper conditions, can be an accurate predictor of latchup threshold linear energy transfer (LET) for most bulk CMOS devices.

Single event upset (SEU) sensitivity dependence of linear integrated circuits (ICs) on bias conditions

The single event upset (SEU) sensitivity of certain types of linear microcircuits is strongly affected by bias conditions. For these devices, a model of upset mechanism and a method for SEU control have been suggested.

On the suitability of non-hardened high density SRAMs for space applications

Several non-radiation-hardened high-density static RAMs (SRAMs) were tested for susceptibility to single event upset (SEU) and latchup. Test results indicate that at present only a few such device types are suitable for use in space applications. Several additional factors such as susceptibility to multiple-bit upsets and to radiation induced permanent damage need to be taken into consideration before these device types can be recommended. One nonhardened SRAM device type has recently been used on a low-Earth-orbit satellite, enabling the upset rate measured in space to be compared to that predicted from ground-based testing. >

Single event functional interrupt (SEFI) sensitivity in microcircuits

The single event functional interrupt (SEFI) sensitivity of several types of microcircuits is measured with heavy ions. While simple microcircuits have not been affected by SEFI, many complex microcircuits are vulnerable to it in varying degrees. Although there are many causes for SEFIs, ion irradiation testing in conjunction with an understanding of device architecture helps refine techniques which can be used to lessen the ill effects caused by SEFI.

Single event effects in pulse width modulation controllers

SEE testing was performed on pulse width modulation (PWM) controllers which are commonly used in switching mode power supply systems. The devices are designed using both Set-Reset (SR) flip-flops and Toggle (T) flip-flops which are vulnerable to single event upset (SEU) in a radiation environment. Depending on the implementation of the different devices the effect can be significant in spaceflight hardware.

Comparative SEU sensitivities to relativistic heavy ions

SEU sensitivity of microcircuits to relativistic heavy ions is compared to that measured with low energy ions of comparable LET values. Multiple junction charge collection in a complex circuit seems to mask the effect of varying charge generations due to different ion track structures. Heavy ions at sub-relativistic speeds may generate nuclear fragments, sometimes resulting in SEUs.

The SEU in pulse width modulation controllers with soft start and shutdown circuits

A study was done of Single Event Upset (SEU) in pulse width modulation (PWM) controllers which feature either soft start or shutdown circuits. Upsets occurring in the soft start circuit of these devices may greatly effect the external circuit depending on the configuration of the PWM.

The impact of ASIC devices on the SEU vulnerability of space-borne computers

Application-specific integrated circuits (ASICs) offer a number of advantages over traditional multicomponent microcircuits, including reductions in both size and power dissipation, and are therefore prime candidates to replace such microcircuits in space borne electronics systems. The results of recent tests of the susceptibilities of various ASIC devices to cosmic ray and trapped proton induced single event upset (SEU) and latchup are reported and are compared to the susceptibilities of the devices that they would replace. This comparison leads to a discussion of the impact of ASIC devices on the SEU susceptibility of spaceborne computers. >

The risk of utilizing SEE sensitive COTS digital signal processor (DSP) devices in space

Digital signal processors (DSPs) sensitive to SEE may be utilized in some space-borne systems, in which the effects of cosmic-rays and trapped protons are limited. Thorough ground testing for SEE is essential in designing an SEE tolerant system, with a minimized risk factor.