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5% color spot in HIC

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#66825

5% color spot in HIC | 16 July, 2012

Why to use 5% color spot in HIC if level 2a-5a are considered bad when 10% is NOT blue ? 10% will be NOT blue(or pink) only after 5% is pink. Then why to keep 5% in HIC ?

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#66830

5% color spot in HIC | 16 July, 2012

Here's what Desco says ... Humidity Indicator Card (HIC) A card on which a moisture-sensitive chemical is printed such that it will change color from blue to pink when the indicated relative humidity is exceeded. This is packed inside the moisture-sensitive bag, along with the desiccant, to aid in determining the level of moisture to which the moisture sensitive devices have been subjected.” (IPC/JEDEC J-STD-033A section 1.5.7) Application 1. The humidity indicator spots will change from blue (dry condition) to pink (humid condition) as the relative humidity changes in the volume of air surrounding the indicator. 2. Relative humidity is indicated at the lavender color. 3. Indicator spots will change within eight hours of being exposed to a change in relative humidity. 4. The humidity indicator spots are reversible, and the pink spots will change back to blue when the volume of air is dried. Humidity indicator cards with pink or lavender spots can be returned to a blue color by placing indicators in a sealed container with 33 grams (1 unit) of desiccant for four hours. 5. The highest humidity indicator spot should be blue before being put into use. 6. The humidity indicator will be at its most accurate at a temperature of 23 °C (73 °F). 7. Avoid contact with indicator spots. Wash any irritated areas with clean water. Handling 1. Store humidity indicators in original container with desiccant when possible and keep sealed. Never reuse a indicator card if it has already changed color. 2. Replace desiccant bag after three openings of container. 3. Store in dry, cool area. 4. Keep indicators out of direct sunlight. 5. Keep humidity indicators away from water or steam. 6. Ammonia gases will damage humidity indicators.

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#66832

5% color spot in HIC | 16 July, 2012

> Why to use 5% color spot in HIC if level 2a-5a > are considered bad when 10% is NOT blue ? 10% > will be NOT blue(or pink) only after 5% is pink. > Then why to keep 5% in HIC ?

We change out the HIC and dessicant when the 5% turns pink to try to keep the humidity under 5% while sealed in the bag.

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#66833

5% color spot in HIC | 17 July, 2012

Referring to IPC/JEDEC J-STD-033B.1 section 3.3.2.2 'The amount of desiccant used, per moisture barrier bag, shall be based on the bag surface area and WVTR in order to limit the interior relative humidity in the MBB to less than 10% at 25°C.' So what's the ideal RH to be maintained inside MBB, 5% or 10% ?

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#66858

5% color spot in HIC | 23 July, 2012

The lower the RH in the MBB the better for all moisture sensitive devices. Maintaining less then 5% will mean no parts of between 2a-5a MSL will need drying before use. The calculation uses 10% because it is a sensible amount of desiccant to use based on the fact that the parts you are sealing in the MBB should be DRY and the desiccant will quickly attract any moisture that is free in the bag or gets into the bag over time keeping the atmosphere as dry as possible, ideally under 5%. Depending on the device thickness and MSL level table 7.1 in jedec33b01 shows how the floor life changes with different RH / Temps that the devices are exposed to. Levels 2a/3 have indefinite floor life at 10% RH.

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