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5

ART28XXT Series

Radiation Performance

The radiation tolerance characteristics inherent in the

ART28XXT converter are the direct result of a carefully

planned ground-up design program with specific radiation

design goals. After identification of the general circuit

topology, a primary task of the design effort was selection

of appropriate elements from the list of devices for which

extensive radiation effects data was available. By imposing

sufficiently large margins on those electrical parameters

subject to the degrading effects of radiation, designers

were able to select appropriate elements for incorporation

into the circuit. Known radiation data was utilized for input

to PSPICE and RadSPICE in the generation of circuit

performance verification analyses. Thus, electrical

performance capability under all environmental conditions

including radiation was well understood before first

application of power to the inputs.

A principal design goal was a converter topology that,

because of large design margins, had radiation performance

essentially independent of normal elemental lot radiation

Completion of first article fabrication, screening and

standard environmental testing was followed by radiation

testing to confirm design goals. All design goals were met

handily and in most cases exceeded by large margin.

These test samples were built with elements that, with the

foregoing exceptions, were not screened for radiation

characteristics. Additional radiation tests on subsequent

ART28XXT manufacturing lots provide continued

confirmation of the soundness of the design goals as well

as justification for the element selection criteria.

The following table specifies guaranteed minimum radiation

exposure levels tolerated while maintaining specification

limits.

performance variations. In the few instances where such

margins were not assured, element lots were selected

from which die were fabricated (and characterized) as

radiation hard devices so that realization of the design

goals could be assured.

Radiation Specification T

Test

Conditions

Min

Unit

Total Ionizing Dose

(2:1 Margin)

MIL-STD-883, Method 1019.4

Operating bias applied during exposure

200

krad

(Si)

Dose Rate

Temporary Saturation

Survival

MIL-STD-883, Method 1021

1E8

1E11

Rads

(Si)/sec

Heavy Ions

(Single event effects)

BNL Dual Van de Graf Generator

83

MeV•

cm²/mg