scope:

This standard establishes the specific requirements for the design of rigid organic printed boards and other forms of component mounting and interconnecting structures. The organic materials may be homogeneous, reinforced, or used in combination with inorganic materials; the interconnections may be single, double, or multilayered.

Purpose

The requirements contained herein are intended to establish specific design details that shall be used in conjunction with IPC-2221 (see 2.0) to produce detailed designs intended to mount and attach passive and active components.

The components may be through-hole, surface mount, fine pitch, ultra-fine pitch, array mounting or unpackaged bare die. The materials may be any combination able to perform the physical, thermal, environmental, and electronic function.

Document Hierarchy

Document hierarchy shall be in accordance with the generic standard IPC-2221.

Presentation

Presentation shall be in accordance with the generic standard IPC-2221.

Interpretation

Interpretation shall be in accordance with the generic standard IPC-2221.

Classification of Products

Classification of Products shall be in accordance with the generic standard IPC-2221 and as follows:

Board Type

This standard provides design information for different board types. Board types are classified as:

Type 1 - Single-Sided Printed Board

Type 2 - Double-Sided Printed Board

Type 3 - Multilayer Board without Blind or Buried Vias

Type 4 - Multilayer Board with Blind and/or Buried Vias

Type 5 - Multilayer Metal-Core Board without Blind or Buried Vias

Type 6 - Multilayer Metal-Core Board with Blind and/or Buried Vias

Assembly Types

A type designation signifies further sophistication describing whether components are mounted on one or both sides of the packaging and interconnecting structure. Type 1 defines an assembly that has components mounted on only one side; Type 2 is an assembly with components on both sides. Type 2, Class A is not recommended.

Figure 1-1 shows the relationship of two types of assemblies.

The need to apply certain design concepts should depend on the complexity and precision required to produce a particular land pattern or P&I structure. Any design class may be applied to any of the end-product equipment categories; therefore, a moderate complexity (Type 1B) would define components mounted on one side (all surface mounted) and when used in a Class 2 product (dedicated service electronics) is referred to as Type 1B, Class 2. The product described as a Type 1B, Class 2 might be used in any of the end-use applications; the selection of class being dependent on the requirements of the customers using the application.