PCB Gold Fingers

Gold Fingers, also known as Edge Connectors, are gold-plated contacts on the edge of a Printed Circuit Board (PCB). They are inserted into a corresponding connector slot, where the connector's pins make contact with the PCB's pads or copper traces to establish an electrical connection. The pads or traces are plated with gold (usually via Electroless Nickel Immersion Gold or electroplating with hard gold) to ensure high conductivity and durability. They are called gold fingers due to their finger-like shape.

Types of PCB Gold Fingers

Gold fingers are typically categorized into three types:

1. Standard Gold Fingers: Feature an even, horizontal array where all PCB pads have the same length, width, and spacing.

2. Uneven Gold Fingers: The pads have the same width but different lengths, and sometimes different spacing.

3. Segmented Gold Fingers (Interrupted Fingers): These pads have varying lengths, and the gold fingers themselves are segmented (disconnected at the front end). This design is often used in rugged or waterproof electronic products to enhance connection stability and durability.

Gold Plating Processes for PCB Gold Fingers

The gold plating process for PCB gold fingers primarily uses two methods:

• Electroless Nickel Immersion Gold (ENIG):

  This gold finish is more cost-effective and easier to solder than electroplated gold. However, its soft and thin composition (typically 2-5 u'') makes ENIG unsuitable for applications that involve the abrasive wear of frequent PCB insertion and removal.

• Electroplated Hard Gold:

  This finish is solid (hard) and thick (typically 30u'' ), making it much more suitable for the abrasive effects of constant PCB usage. Hard gold is often alloyed with cobalt to increase its wear resistance.