The bounding rule in circulation is roughly rail to rail, twenty microseconds, traceable to a RADECS 2001 hardness assurance paper and repeated ever since. It is not a worst case. Fitted to 1,225 publicly citable heavy ion records over 641 parts, twenty microseconds sits at the 77th percentile of measured operational amplifier transient widths. Close to one in four tested op-amps exceeds it.
The documented counterexamples are not obscure. The LM6144 produces transients to about 1.5 ms through a bias network that latches rather than glitches. The RH1014, a radiation hardened part, produced pulses roughly eight times longer than the commercial LM124 tested beside it. The corpus here contains an operational amplifier with a laser induced event longer than 600 ms.
So the useful output is not a single number but a distribution, and a choice of how much of it you want to cover. That is what the advisor below returns. It also separates two things that get conflated: a self recovering transient, whose width is set by charge collection and circuit bandwidth, and a latched or shutdown event, whose duration is set by a soft start or restart timer and which is a functional interrupt rather than a transient. Roughly 32 percent of linear regulator records that report a duration describe the second kind.
Pick the family and the rails. The envelope is the fitted quantile of the measured population at your chosen exceedance probability, so a 95 percent bound means roughly one part in twenty of that family would be expected to exceed it. The maximum actually observed is shown beside the fitted value, because where the two diverge the fit is extrapolating past the data and you should know it.
An analog cross section is not a property of the part on its own. A test only counts an event if it crosses the discrimination level the tester chose, so the number that gets quoted is a joint property of the device and the oscilloscope setting. Raise the level and the cross section falls, the apparent threshold LET rises, and the rate estimate that depends on both falls faster still. This is the single most common way an analog number is misread. In the corpus behind this page, only 169 of 1,225 records state the discrimination criterion at all.
You have a captured waveform and you want to know what you are looking at, whether it is credible, and what to check next. Select what you observed. The output is a ranked set of hypotheses with the evidence for each and the measurement that would separate them, not a verdict.
The mechanism, the signature, the test conditions that change the answer, and the things the literature says are commonly got wrong. Fitted numbers are shown per family with the record count behind them, so you can see which are supported and which are borrowed from the pooled prior.
The corpus is 1,225 single event transient test records covering 641 distinct parts, drawn from publicly citable sources: IEEE Radiation Effects Data Workshop papers, NASA Goddard radiation test reports and RADECS proceedings. Records from sources that are not publicly citable were held out of the published fit entirely and used only as a sensitivity check; including them shifts the pooled amplitude location parameter by -0.010 and the pooled width location parameter by +0.087 in natural log units, which is to say it changes nothing material. Only heavy ion records are in the published model. Proton records (299) and pulsed laser records (183) are fitted separately, because proton transients are systematically shorter and smaller and because a laser result carries no LET equivalence.
The measurements live in free text, not in structured columns. A first pass using pattern matching was audited against forty records adjudicated by hand and scored three correct out of forty: supply and bias voltages were being read as transient amplitudes in more than half the sample. That approach was abandoned. Every record was instead read and adjudicated individually against a written specification that separates a transient amplitude from a supply voltage, a discrimination threshold and a rated maximum, and separates a transient width from an irradiation time, a laser pulse width and a tester dead time. The result was scored against the independent hand adjudication on the overlapping records and agreed on 35 of 35 of them. The specification is published with the model so the judgement calls are inspectable rather than implicit.
Amplitude is expressed as a fraction of the rail, which is the quantity that transfers between parts with different supplies, and is capped at 2.0, being a rail to rail excursion on a split supply measured against one rail. Width is in seconds. Each is given a lognormal, fitted by maximum likelihood over interval censored observations, because a record saying the worst case lasted more than five microseconds is a left censored observation of the worst case and not a measurement of five microseconds. Discarding those records would bias the tail downward, which is precisely the tail the bound depends on. Families with few observations are shrunk toward the all family pooled prior with weight n over n plus 12, and any family whose bound is carried by the pooled prior rather than its own data is labelled as such in the advisor.
Self recovering transients and latched or shutdown events are fitted as separate populations. This is not a cosmetic split. Pooling them produces 99th percentile widths in the tens of milliseconds for operational amplifiers and tens of seconds for supervisors, which is an artefact of mixing a charge collection process with a soft start timer. Classification uses the recorded description of the event, and any event lasting a millisecond or more is treated as latched unless the record explicitly says the part recovered on its own.
The model was fitted without reference to the individual published results below, so the agreement is a check rather than a construction.
Sources for the mechanisms, signatures and published values on this page.
This guideline was written from published literature and from a test record corpus assembled from public sources. It is not a reproduction of any organisation's internal document. Corrections are welcome through the community forum or by getting in touch. Related tools: Power Device Derating Advisor, SEL Threshold Predictor, SEE Rate Assessment, Standards and Data Sources.
