Pdf [top]: Ipc-4556

The finish must satisfy wetting requirements under both lead-free (SAC305) and traditional tin-lead solder profiles.

As IPC standards are ANSI-accredited, the American National Standards Institute also sells the PDF.

The standard establishes the strict requirements for the deposition of ENEPIG surface finishes on PCBs. It defines the necessary thickness ranges for each metal layer, specifies the criteria for solderability and wire bonding, and outlines the testing methodologies required to confirm compliance. ipc-4556 pdf

As IPC standards are copyrighted, the full document is generally available for purchase through the IPC Official Store. You can also find technical summaries and Tables of Contents (TOC) at sites like Electronics.org . IPC-4556 - Specification for Electroless Nickel

Protects the palladium from environmental oxidation and maintains a low contact resistance for keypads and switches. Testing and Quality Assurance Protocols The finish must satisfy wetting requirements under both

| Class | Description | Typical Applications | | :--- | :--- | :--- | | | General Electronic Products | Consumer electronics, toys, simple remote controls | | Class 2 | Dedicated Service Electronic Products | Industrial controls, automotive (non-safety), computers | | Class 3 | High Performance Electronic Products | Medical implants, aerospace avionics, military systems |

Before IPC-4556, the industry suffered from inconsistent ENIG applications. Common failures included "black pad" syndrome (a brittle, non-wettable nickel layer) and gold embrittlement. IPC-4556 was created to eliminate these failure modes by standardizing the thickness, purity, and morphology of both the nickel and gold layers. It defines the necessary thickness ranges for each

The use of IPC-4556 PDF offers several benefits to manufacturers, including:

IPC-4556 - Revision A - Global Electronics Association: Store