Gold Fingers and Their Use in the World of PCBs

Gold Fingers and Their Use in the World of PCBs

In the realm of PCB assembly and manufacturing, there are three different methods that come with printing the prototype PCB’s legend. The legend is what the engineer uses to figure out the component designators, switch settings, and test points — all helpful components need when assembling, testing, and servicing the prototype circuit boards.

However, there are more details that go into this legend, including gold plating. Here is a beginner’s guide to this specific PCB fabrication process.

What is gold plating, more specifically gold finger?

Gold finger is the gold-plated connectors that are on the edges of the printed circuit board prototype. They are similar to fingers in that they are long and narrow.

What are they made from?

The specifications for these have to be exact; flash gold must be used and the thickness cannot go over 3Us to 50Us. This is so the flash gold, which is one of the hardest golds available, will last a long amount of time and won’t need repair.

What is their purpose?

Gold fingers are edge connector contacts and are used to electroplate pads onto the board. The idea behind a gold finger is to help protect the printed circuit board prototypes from wear and tear. If applied correctly, with the right thickness, they are expected to last upwards of 1,000 cycles before there is any need of repair.

How are gold fingers used?

These little fingers are quite versatile, and they have many different uses depending on their intended purpose. Some of these uses include:

  • Provides connections for network transfer data.
  • Attaches specialty adaptors.
  • Connects different devices to the board.
  • Can be used as audio adaptors.

Are there specific design specifications?

Yes. As we mentioned previously, there are some specifications depending on the need and use of the board. However, despite this, there are some design rules that must be followed no matter the board’s intended purpose. This includes:

  • No plated through holes can be included anywhere near the gold fingers.
  • No soldermask or screen printing can be included near the gold fingers.
  • The gold fingers should always be placed facing outward of the board’s center.

If you are interested in learning more about how these interesting little gold fingers work in the world of printed circuit boards, please contact our professionals today.

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