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Electronics => Projects, Designs, and Technical Stuff => Topic started by: Alex Eisenhut on November 01, 2019, 03:45:17 am

Title: matte tin pin contact with ENIG PCB
Post by: Alex Eisenhut on November 01, 2019, 03:45:17 am
Good day!
Samtec OPP connector
http://suddendocs.samtec.com/catalog_english/opp.pdf (http://suddendocs.samtec.com/catalog_english/opp.pdf)
As you can see these are spring-formed matte-tin-plated pins that mate to a pad on another PCB.
They say it should mate to a tin-plated pad.
Page 3:
http://suddendocs.samtec.com/prints/opp-xx-01-x-s-x-xx-footprint.pdf (http://suddendocs.samtec.com/prints/opp-xx-01-x-s-x-xx-footprint.pdf)

So what happens if the pad is ENIG instead? Will the Sun go red giant? Will Jupiter turn into a quasar?

Will there be some kind of tin-gold intermetallic shenanigans ??

Samtec says this is "not recommended" and won't tell me more than that. Unfortunately the mating board is already done, it's ENIG.
Title: Re: matte tin pin contact with ENIG PCB
Post by: wraper on November 01, 2019, 04:54:45 am
Likely you will start having contact failures after few months to years.
Quote
Unfortunately the mating board is already done, it's ENIG.
Then tin the pads and thoroughly clean from flux. Although I don't advise using connectors of such style (springy) in non gold plated variants. If you want to go with tin, use connectors which strongly bite into solder on the pad. Such as commonly used in HDDs.
Title: Re: matte tin pin contact with ENIG PCB
Post by: Alex Eisenhut on November 01, 2019, 11:36:01 am
Yeah this connector wasn't my choice, I did leave paste on the mating pads and when the boards got assembled I got an earful when my boss saw the solder.
I guess it's a wait and see thing now...  :-//