What is HAST (Highly Accelerated Stress Test)

What is HAST (Highly Accelerated Stress Test)

Definition and Test Standards

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HAST

The highly accelerated temperature and humidity stress test (HAST) is a highly accelerated

method of electronic component reliability testing using temperature and humidity as the

environmental parameters. HAST is also known as the pressure cooker test (PCT) or

unsaturated pressure cooker test (USPCT). Its purpose is to evaluate a test sample’s

humidity resistance by increasing the water vapor pressure in a test chamber to an

extremely high level above the partial water vapor pressure inside the test sample. This

process temporally accelerates the infiltration of moisture into the sample.

HAST test standards

HAST is a more accelerated version of accelerated humidity-resistance testing.

Compared to high-temperature/high-humidity testing (at 85°C/85% RH), HAST causes more component

contact due to moisture-driven corrosion and more insulation deterioration. HAST is done

mainly on plastic sealed components. The table that follows shows the most common

HAST-related test standards. The test is performed at a specified temperature and relative

humidity, or pressure. The atmosphere normally has a temperature of at least 100°C, in a

state of water vapor pressurization. HAST is sometimes classified as a combined test when

pressure is also considered as an environmental parameter. There are saturated and

unsaturated varieties of HAST. The former is typically done at conditions of 121°C and 100%

RH, and the latter at conditions of 110, 120 or 130°C and 85% RH. Tests done with the

electronic component’s power on are usually the unsaturated type. HAST is a fairly extreme

test, with an acceleration factor of anywhere from tens to hundreds of times under

conditions of 85°C and 85% RH. This extreme acceleration makes it important to check

failure modes.

Table 1 Common HAST-related standards

(Note that standard conditions may be revised, so should be confirmed individually.)

ANDK socket can meet your HAST test,any package and any questions,welcome to your inquiry.

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