On Thu, 07 Jun 2007 01:47:22 -0600, Forrest W Christian wrote:

>Carey Fisher wrote:
>
>>Forrest,
>>What's MSL and why does it matter?
>>
>Others have answered with what it is... basically a rating which has to 
>do with absorbtion of moisture from the air which vaporizes during 
>soldering cracking the package (or doing other damage).
>
>What is scary is how many packages are at MSL 3 or above.  What is 
>biting me are the regulators I want to use which are in a TO-263 package 
>which is basically a surface mount version of the TO-220.  Once I open 
>the package I have to use all of them within 7 days or I have to bake 
>them at 125*C for at least 8 hours to dry them out before I do use them.
>

Something doesn't sound right about that. Aren't there provisions in
MSL handling procedures that allow for resealling the devices that
won't be used over the next 7 days? 

You may be able to avoid some bake-outs by doing this. I'll see if I
can find a link on the topic. 


Regards, Bob

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist