Author Topic: Are ALL RoHS Compliant SMDs Moisture Sensitive?  (Read 2092 times)

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Offline NY2KWTopic starter

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Are ALL RoHS Compliant SMDs Moisture Sensitive?
« on: October 04, 2023, 10:50:25 pm »
I am a hobbyist who likes to build and repair.  I read that lead-free solder is more prone to moisture degradation.  Today I received a few RF switches (HMC1118, Analog Dev) from Mouser that came double-bagged with big label warning the chips were Moisture Sensitive and gave specs that it should be mounted  with "168 hours" after bag is opened AND if Humidity Indicator Card reads >10% the SMD should get baked per IPC/JEDEC J-STD-033 specs .

I pulled the datasheet and it does not mention anything about moisture sensitivity or special handling. Is this a Mouser liability disclaimer or something broader along RoHS guidelines? 

Jerry NY2KW
 

Offline TimFox

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Re: Are ALL RoHS Compliant SMDs Moisture Sensitive?
« Reply #1 on: October 04, 2023, 11:20:22 pm »
I believe that the short lifespan out of the sealed package is because the metal surfaces (to be soldered by SMT processes) become polluted in a moist atmosphere, and the solder may not stick.
 

Offline Jackster

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Re: Are ALL RoHS Compliant SMDs Moisture Sensitive?
« Reply #2 on: October 04, 2023, 11:25:40 pm »
Pretty much all IC packages are sensitive to moisture and should be shipped in such a bag.
As far as I know, the plastics love to soak in water.

Here are the standards
https://www.surfacemountprocess.com/uploads/5/4/1/9/54196839/j-std-033b01.pdf

Offline Infraviolet

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Re: Are ALL RoHS Compliant SMDs Moisture Sensitive?
« Reply #3 on: October 05, 2023, 10:15:36 pm »
To my understanding, certainly from my experience, for small scale hobbyist use, if you're soldering with wire solder and an iron, or with applying paste solder then using either an iron tip or precisely aimed hot air gun to heat it, you'll probably get away with ignoring the moisture warnings so long as you keep parts in the bag and reseal it with some wrappings of tape between uses. Things would be more problemtic at industrial scale, and with any soldering process where the whole board gets heated during soldering.

Also, I think some sellers might just stock that one sort of bag with moisture warnings as the packaging in which they'll ship anything ESD sensitive. They might not bother to have any bag in stock for ESD protection but which doesn't carry the moisture warning. That said, I think some parts which are moisture sensitive don't warn so on their datasheets. I hear all SMD LEDs are strongly moisture sensitive, but I've often seeen datasheets for specific models of them which make no mention of moisture.
« Last Edit: October 05, 2023, 10:19:10 pm by Infraviolet »
 

Offline aeg

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Re: Are ALL RoHS Compliant SMDs Moisture Sensitive?
« Reply #4 on: October 06, 2023, 02:20:06 am »
I pulled the datasheet and it does not mention anything about moisture sensitivity or special handling.

Does page 11 of your copy of the datasheet not say the part is MSL3?
 

Offline aeg

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Re: Are ALL RoHS Compliant SMDs Moisture Sensitive?
« Reply #5 on: October 06, 2023, 02:20:55 am »
I believe that the short lifespan out of the sealed package is because the metal surfaces (to be soldered by SMT processes) become polluted in a moist atmosphere, and the solder may not stick.

False. MSL is due to popcorning, not solderability.
 
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