Overview - IEC 61188-7:2017 (Electronic component zero orientation for CAD library construction)
IEC 61188-7:2017 is an international standard that defines a consistent technique for describing electronic component zero orientation and associated land pattern geometries for CAD library construction. Its purpose is to enable unambiguous data capture and transfer between engineering, PCB layout, fabrication and assembly systems - supporting global trading partners and automated manufacturing. This edition clarifies orientation concepts (Figure 1 corrected), replaces the term “rectangle” with “polygon”, and designates Level B as the preferred orientation level for new libraries.
Key topics and technical requirements
- Scope: Establishes uniform rules for component orientation, land pattern origin points and the geometry metadata needed in CAD libraries.
- Basic rules:
- Components and land patterns are defined in top view.
- The component point of origin is marked (commonly “+” or “x”).
- The component, land pattern and courtyard polygon should share the same origin coordinates in the library.
- The origin of a land pattern may differ from the placement origin; this must be clearly defined.
- Pin one (or other polarity indicators) shall be positioned and identified consistently - the standard requires pin one to be on the left-hand side of the component description.
- Recommended origin selection is the centroid of the component body where practical.
- Levels: Two orientation classification levels (Level A and Level B) are defined; Level B is recommended for new libraries.
- Component classes covered: Discrete devices, diodes, transistors, ICs, BGA, resistor arrays, connectors and one-terminal components - with tabulated land-pattern conventions and origin-point rules.
- Normative references: Works with other parts of the IEC 61188 series (notably IEC 61188-5-x for attachment/land/joint considerations).
Practical applications and users
Who benefits:
- PCB designers and CAD library managers building consistent component libraries
- CAD tool vendors and EDA integrators implementing standard orientation rules
- Component manufacturers and distributors supplying CAD models
- PCB assemblers and contract manufacturers using automated pick-and-place and assembly machines
- Supply chain and data-exchange platforms requiring unambiguous component metadata
Practical uses:
- Creating a “one-world” CAD library to reduce manual rework and data translation
- Enabling automated assembly by ensuring consistent zero orientation and pin identification
- Improving cross-company data exchange, design-for-manufacture (DFM) checks and test-program generation
Related standards
- IEC 61188 family (Printed boards and printed board assemblies – Design and use), especially IEC 61188-5-x (attachment/land/joint considerations) for land-pattern definitions and solder joint requirements.
Keywords: IEC 61188-7:2017, electronic component zero orientation, CAD library construction, land pattern, CAD library, component orientation, PCB, pin one, polygon courtyard, Level B.