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Thru-hole Moisture sensitivity

Rich Z

#4469

Thru-hole Moisture sensitivity | 11 April, 2000

Is there any connection with mositure sensitive components and thru-hole devices? All of my research material directs me toward Surface Mount devices.

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#4470

Re: Thru-hole Moisture sensitivity | 11 April, 2000

Rich: Now that�s a great question!!! You�re corrrect.

Primary-side temperature is the driver of the differences in the sensitivity to moisture between SMT and PTH devices that you�re finding. * Primary-side temperature for SMT ~= Secondary-side temperature for SMT ~= 220 to 245�C * Secondary-side temperature for PTH ~= 235 to 260�C * Primary-side temperature for PTH ~= 110 to 130�C

So on the surface (so to speak), PTH components get plenty warm enough on the wave to boil water, but you�ve got to also consider component mass, heat dissiaption of the soldering environment, resistance of the component to fracture, and other stuff that tend to limit the damage to PTH components from moisture absorption.

Good luck Dave F

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