[Elecraft] Re: IC pins

[Jack Brindle]

On Jan 4, 2005, at 9:31 AM, Tom Hammond wrote:

>> Anyway, it occurs to me (and has often occurred to me) why do we have 
>> to reform the pins on ICs?  How come they aren't manufactured the 
>> "right" shape?  I go into ESD-panic mode every time I have to re-form 
>> them and some have been a complete pain to match up to their socket.
>
> I wish I could respond as to why they must be manufactured with the 
> pins 'sprung out'... seems they could just as easily be bent properly 
> from the factory. But I'll bet some one WILL be able to offer a 
> logical reason.

This is actually an easy one. The pins are shaped that way in order to 
allow the placement machinery to grab the chip and properly place it. 
If the pins were straight, the chips would tend to fall out of the 
machine, causing lots of problems.

It is interesting that some chips are not angled as much - specifically 
the side-brazed ceramic DIPS used in older EEPROMS. They are still 
angled, though.

>> Anybody got a fool-proof, first-time technique for this?
>
> Follow the instructions in the manual. Grasp the IC by its ends, press 
> one side down onto the desktop (I often place it against a metal 
> ruler, for added ESD protection, though I've NEVER damaged an IC as a 
> result of ESD) and roll the IC inward a bit, to reform the leads.
>
> They also make pin straighteners, but they're not all that much better 
> than just doing it by hand.

There are IC insertion devices that clamp around the DIP packages and 
properly align the pins while you insert them into the PCB. No idea the 
cost, or even current availability. They used to be fairly common 15 or 
20 years ago (remember that far back, Tom? ;-)

I use the "straighten it against the desk" ritual. As far as I know, I 
haven't lost a chip in 30 years. But then during that time I lived in 
South Florida, Georgia and Sillycon Valley, where the static levels 
tend to be fairly low (as opposed to places like Washington DC, which 
has its own static level, but thats another story... ;-)


-Jack Brindle, W6FB
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