[hpsdr] Altera IC's: moisture sensitivity

Gerd Loch g.loch at nt-electronics.de
Fri May 1 15:43:28 PDT 2009

Hi Eric,

this is an advice that should not be ignored.
However it is mainly provided for reflow soldering which is the normal
process for soldering such components.
The device is mounted and bonded to a small pcb made of glass reinforced
epoxy which is also used for "normal" pcb's. This material is hygroscopic
and incorporates humidity from the ambient air.
During reflow soldering the incorporated humidity explodes and leads to
delamination of the carrier pcb and to discontinuities in traces and vias.
This effect is called "popcorn effect"
It is not so critical if you solder the device manually pin after pin and
not heating the complete device in a short time up to 250°C.
However you should keep the devices in the aluminized foil which contains
some drying material until you are going to solder the device to your board.
You will also find a humidity indicator in the foil which indicates if the
content of the package has seen too much humidity. If the indicator is still
blue you have not exceeded the acceptable level of humidity. If the
indicator shows a red colour you should bake the device at 120-130°C for 48
hours before reflow soldering.

73, Gerd

----- Original Message ----- 
From: Erik N Basilier 
To: hpsdr at lists.hpsdr.org 
Sent: Friday, May 01, 2009 12:29 AM
Subject: Altera IC's: moisture sensitivity

I ordered components to build an OZY. The Altera IC's from Arrow came in
huge opaque sealed bags. My first thought was I had been sent circuit
boards, or massive quantities of IC's. On closer examination I discovered
labeling that said the contents is moisture sensitive, and if reflow
soldering or other high-temperature process is to be used, it must be done
within 168 hours of opening the bag. There was a hint about some kind of
moisture monitoring device in the bags, which might explain the bulk. I
don't have experience with reflow soldering, but I am guessing I can ignore
the issue as long as I do the soldering the amateur way with iron and added
solder. It will be some time before I will have time to do the soldering,
but I would like to verify what is in the bags a.s.a.p.

Thanks and 73,
Erik K7TV

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