Tech Forum

Personally I always use the "machined" gold plated contacts (Machined contacts are round, and have 3 to 4 gold fingers internally) the cheaper tin sockets require more force, and this force can (and does) bend the IC pins. Once you get above 18pins it is really difficult to insert IC's into tinned leaf sockets.

Gold plated contacts are highly resistant to corrosion. If you are designing equipment that is going to potentially operate in humid environments or where reliability is paramount, then using sockets with gold plated contacts can be a good investment. For most applications though, conventional machined-pin sockets provide excellent performance and the added cost of gold plating will not buy you much.

Most consumer equipment uses inexpensive stamped pin sockets and even those are normally adequate.

Depends on the environment that the project will be operating in. Gold plated sockets are usually specified for high-reliability, that is, in mission-critical or life-critical applications. Tin plated contacts don’t like lots of high frequency vibration, such as near heavy industrial equipment. It also doesn’t tolerate humid environments. Gold plating is great for use in humid environments, and is better than tin in high vibration environments.

There’s not a lot of difference in contact resistance, and you won’t gain anything with gold. If your project will be used in a humid or corrosive environment, then I suggest a conformal coating be applied over the entire circuit board. Gold plating comes with its own unique problems, the main one being separation of the gold plating from the plated surface, causing a failed connection, or worse, an intermittent connection.

I’ve used tin plated sockets for many years, and never a problem that could be traced to the sockets. My money is on the tin plated sockets.

Always go for the gold with chip sockets and “wire wrap” socket pins! The main reasons are:
 

1) Excellent corrosion resistance, which translates to more reliable connections. Tinned contacts will electrically degrade due to oxidation, even after the chips are inserted.
 

2) Better spring (mechanical) contact between the socket and chip pin. Tinned sockets are simple “leaf compression” types that are prone to “chip creep” (i.e., the chips push out of the socket over time) caused by thermal effects (i.e., heating when powered on and cooling when powered off), which means you have to occasionally re-seat the chips (i.e., pushing them back into their sockets with a “crunch-like” sound when they re-seat). Gold sockets are machined and use “grip fingers” that, literally, clamp down on the chip pins, virtually eliminating chip creep. Also, after crunching a loose chip in a tinned socket, it’ll creep out again at an increasingly faster pace as the tension in the leaf springs increasingly degrades with each re-seat operation (also resulting in degraded electrical connections - see 1 above).
 

3) Mechanical security of installed chips. Referring to 2) above, a creeped-out chip will eventually fall out of its’ socket if the board is jarred. Chips installed in gold sockets, again because of the clamping effect on the pins, will never fall out if the board gets jarred. FYI: I type this from 35 years of industry experience having to find and re-seat loose chips in tinned sockets that caused intermittent (and frustrating!) device malfunctions. I rarely (almost never) had creep, etc. problems with gold-plated (machined) chip/wire-wrap sockets.

I would get the less expensive tin sockets, unless you will have the project in a corrosive environment (and you would also have to deal with possible wire corrosion). In using many sockets over the years, I have not had any problems with tin. Get the “springy” side-contacing socket like (www.digikey.com/product-detail/en/A08-LC-TT/AE9986-ND/821740) rather than the machined pin type of socket. I have had some machined pin sockets making bad contact with the IC.