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In electronics reliability, what are 'HALT' and 'HAST'?


Frequently Asked Questions

HALT stands for Highly Accelerated Lifetime Testing and covers all methods employed to try to estimate the expected life of a product using accelerated techniques. These include vibration testing; mechanical fatigue methods; thermal cycling with or without humidity control; power cycling, etc. These methods are useful for establishing the comparative performances of products and, by using various mathematical models, can be used to estimate actual service lives.

HAST, the acronym for Highly Accelerated Stress Testing, is used to estimate the performance of an assembly with relation to moisture ingress, as in tropical climates, for example. Tests are generally carried out in an autoclave at temperatures above 100°C and with relative humidities above 90%. Within the validation limits, HAST can give accurate lifetime estimates in products where moisture controlled corrosion is the primary failure mode.

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