An Introduction to ANSI and IPC Joint Standards

Introduction

The IPC, the acronym for the Association Connecting Electronics Industries, has issued joint standards with ANSI International that apply to electronics such as printed circuit cards.

These printed circuit cards (PCBs) and printed wiring boards (PWBs) are in everything from your cell phone to the cell phone tower, your computer to the motherboards in the server farm processing your internet queries. IPC/ANSI joint standards cover the materials, design information, supply chain data formats and assembly methods used to manufacture circuit card assemblies of all sizes.

Circuit cards such as the one in this cell phone are designed and manufactured in accordance with ANSI/IPC joint standards.
Circuit cards such as the one in this cell phone are designed and manufactured in accordance with ANSI/IPC joint standards. | Source

ANSI/IPC Joint Design Standards

ANSI/IPC 2222 is the joint standard for rigid printed wiring board or PWB design. ANSI/IPC 2225 applies to the design of boards with organic multichip modules called MCM-L and assemblies that use them. ANSI/IPC 4130 gives the ANSI and IPC joint recommendations for designing and selecting the core of the circuit board. Print circuit board cores may be cellulose paper, nonwoven glass, polyester or other materials.

According to “Reduce Your Engineering Drawing Errors: Preventing the Most Common Mistakes” by Ronald Hanifan, ANSI/IPC joint standards such as ANSI/IPC 325 and ANSI/IPC D351 on the presentation of PWB designs are considered sub-tier standards to ANSI drafting standards like ASME Y14.24.

ICP A-610, the standard on the acceptability of electronic assemblies, is the most commonly referenced IPC standard. While ICP A-610 is not a joint standard with ANSI, it is available through ANSI’s website.

IPC Standards on Communications

ANSI/IPC 2547 gives the requirements for shop floor equipment communication messages. These messages, abbreviated as CAMX, are used for communications between printed circuit board test, inspection and rework equipment. When an automated printed circuit board inspection machine finds defects in wiring or an automated test set discovers shorts, this standard defines the messaging to be used.

PDX Standards

ANSI/IPC 2571 outlines the requirements for Product Data Exchange or PDX for short. This XML data format allows mechanical engineers designing heat sinks and structural components of a printed circuit board to exchange information with electrical engineers designing the circuits and internal wiring.

ANSI/IPC 2576 gives the requirements for PDX when used for as-built data, such as a vendor sending information back to a customer with the list of components used to build the printed wiring board and location of all wires, including “blue wire” modifications. ANSI/IPC 2578 gives the standard to be used for the Bill of Materials or BOM of a printed wiring board. The Bill of Materials lists the parts, part descriptions, part numbers and quantity of each to be used to build the printed wiring board. ANSI/IPC D-350 gives the standard for the printed board description in digital form.

Printed circuit boards are typically manufactured per IPC standards.
Printed circuit boards are typically manufactured per IPC standards. | Source

Material Specifications

ANSI/IPC 4110 gives the specifications for non woven cellulose paper used on printed circuit boards. This cellulose, while based on natural material, is treated so that it will not burn while in contact with electrical components. CEM-2 printed circuit boards have a cellulose paper core.

ANSI/IPC 4411-K gives the material specifications for para-aramid fibers used in printed circuit bards. ANSI/IPC 4130 gives the standards used for nonwoven glass used in printed circuit cards. The glass is used in composite layers to create the printed circuit board.

ANSI/IPC 4552 gives the requirements for electroless nickel immersion gold plating, called EMIG for short. Electroless nickel immersion gold plating is more expensive than epoxies used to protect ball grid array chips and electrical connections, but it also offers greater protection. ANSI/IPC CF-150 gives the material specifications for copper foil used in PWBs. ANSI/IPC standard FC-232C covers adhesive coated dielectric films used as coversheets on flexible printed wiring boards. ANSI/IPC FC-233 covers flexible adhesive bonding films that may hold PWB layers together or secure flexible wiring to the board.

ANSI/IPC L-125 is the specification for plastic substrates. ANSI/IPC FC-241C covers flexible metal-clad dielectrics used during the fabrication and manufacture of flexible printed wiring boards. ANSI/IPC SM-817 is the standard for dielectric surface mounting adhesives. When an electronic component is glued onto the board with an electrically conductive adhesive, this standard applies to the adhesive used to attach the SMT component.

ANSI/IPC SM-817 gives the general requirements for Surface Mount Technology adhesives. ANSI/IPC SM-840B is the standard for permanent polymer coatings used on printed wiring boards, also called solder mask. However, you need to look to the joint standard IPC/ECA J-STD-002C for the standard on solderability tests.

Sources of These Standards

Many IPC standards originated as military standards, called mil spec. These standards were used to build military and defense industry electronics. IPC standards replace the military standards they evolved from, unless they themselves are superseded by ANSI, IEEE or IEC standards.

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