Palladium plating on pins of common 7400 series ICs?

[Auggie]

I was reading this datasheet today for a project I'm working on and found an interesting footnote. Look on the lower left-hand corner of page 5: "* Pd plating"

http://pdf1.alldatasheet.com/datasheet-pdf/view/64008/HITACHI/74LS164.html

 

[Irons2]

Those surface mount devices are quite small. Look for the ceramic ones from the 70's. Those flatpacks have some worthy Pd plating.

 

[Auggie]

Those surface mount devices are quite small. Look for the ceramic ones from the 70's. Those flatpacks have some worthy Pd plating.

Aha. I didn't notice that was a surface mount version.

Are you saying all the DIP package type ICs have palladium plating on the legs?

http://www.twistywristarcade.com/182-505-large/74ls152.jpg

 

[Irons2]

Those surface mount devices are quite small. Look for the ceramic ones from the 70's. Those flatpacks have some worthy Pd plating.

Aha. I didn't notice that was a surface mount version.

Are you saying all the DIP package type ICs have palladium plating on the legs?

http://www.twistywristarcade.com/182-505-large/74ls152.jpg

Lead/Tin solder is more likely. Surface mount devices might have a PM coating to aid soldering, since the process is different than thru-hole boards, but even those are likely to be solder plated. I used to do surface-mount rework as part of my job as a Diagnostic Tech for Digital Equipment Corp. Most of what I saw looked like solder, not PM. Even if it was a PM plating, the value would be very little. If you had a large quantity of parts, it would be worth processing, otherwise, it's just a curiosity.

 

[NoIdea]

One of those uncertain area's, not sure if there are PM's in them their bits. When it comes to IC's this is roughly how i do it, more detailed poste will follow as soon as i finally figure out what im doing. :mrgreen:

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=39&t=15086&p=152651#p152651

Cheers

Deano

 

[macfixer01]

As Irons2 said, lead/tin solder coating was the norm. However I've seen many old 7400 series chips from the early 1970's which have their pins turned black and/or are coated with a powdery black material (mostly Texas Instruments brand as I recall). I have to assume maybe they were silver plated, which turned into silver oxide or silver sulfide over the years?

Edit - I meant to say this is for the through-hole DIP type packages.

 

[NoIdea]

....I have to assume maybe they were silver plated, which turned into silver oxide or silver sulfide over the years?

You are right on about it being silver and easy to spot on the older stuff. Well spotted :mrgreen:

Deano

 

[tek4g63]

I worked manufacturing electronics for 13 years. Most components with silver colored leads were referred to as " tinned". A heavy tin based solder was lightly coated on them to prevent oxidation from forming on the copper, witch would prevent them from soldering properly.

Not all parts were. " tinned" some were gold plated.... ect... Just though I would share the term used in industry.