IEC 61188-6-4:2019

Overview

IEC 61188-6-4:2019 is an international standard developed by the International Electrotechnical Commission (IEC) that sets out the generic requirements for dimensional drawings of surface mounted components (SMD) with a focus on land pattern design. The standard aims to eliminate issues in land pattern design that result from insufficient or incorrect use of SMD dimensional data. It is a critical reference for anyone involved in the design, manufacturing, and assembly of printed boards and printed board assemblies, particularly where SMDs are prevalent.

This standard is applicable to a wide range of SMDs used in semiconductor devices and electronic components, promoting better consistency, reliability, and manufacturability across global supply chains.

Key Topics

IEC 61188-6-4:2019 addresses several important topics from the perspective of land pattern design for SMDs:

• Dimensional Drawing Requirements: Specifies generic requirements for 2D and 3D dimensional drawings of various types of SMDs relevant to land patterns.
• SMD Types Covered: Includes end-terminal type (rectangular, square, or cylindrical terminals), gull-wing terminals, inward L-shaped ribbon terminals, under-body L types, bottom surface terminal types (like BGA, QFN, LGA), and flat lug terminals.
• Dimensional Symbols and Consistency: Outlines the use of dimensional symbols and ensures consistency in dimensions across various drawings and data sets.
• Land Pattern Design: Guides the calculation and specification of land width and length, location of lands, and their relationship to SMD terminals.
• Courtyard and Clearance: Provides requirements for defining the courtyard – the monopolized area of the SMD on a PCB – and the related clearances ensuring proper spacing for manufacturing and inspection.
• Height Parameters: Specifies requirements for indicating component and terminal heights, critical for spatial design and soldering reliability.
• Coplanarity and Placement: Addresses coplanarity requirements for SMD terminals to ensure robust solder joints and reliable assembly.
• Metal and Resin Differentiation: Requires clear distinction between conductive metal and insulating resin in technical drawings for accurate land pattern interpretation.

Applications

IEC 61188-6-4:2019 is instrumental in several areas within the electronics design and manufacturing domain:

• PCB Land Pattern Design: Utilizes dimensional requirements to create effective land patterns that minimize assembly errors and improve yield.
• Component Library and Data Management: Supports standardized data formatting for SMDs in CAD libraries, streamlining design automation and collaboration.
• Manufacturability and Inspection: Enhanced description of courtyards and clearances facilitates automated optical inspection (AOI) and rework processes.
• Quality and Reliability: Reduces the risk of defects such as tombstoning and insufficient solder joints by ensuring consistent and comprehensive SMD drawings.
• Global Supply Chain Integration: Enables clearer communication and interoperability between component manufacturers, PCB designers, and assemblers.

Related Standards

For comprehensive design and manufacturing processes, IEC 61188-6-4:2019 should be used in conjunction with the following standards:

• IEC 60194: Terminology for printed board design, manufacture, and assembly.
• IEC 60194-2: Vocabulary for electronic technologies and printed board assembly.
• IEC 61191-2: Requirements for SMD solder joint quality.
• IEC 61188 Series: Other parts cover generic land pattern design and specific component type guidelines.

Practical Value

Adhering to IEC 61188-6-4:2019 helps organizations reduce errors, improve interoperability, and increase confidence in PCB assembly outcomes. It streamlines land pattern design by ensuring that SMD drawings are consistent, accurate, and easy to interpret, supporting both performance and manufacturability for modern electronic designs. This standard is essential for engineers, designers, and manufacturers who aim to meet global best practices in surface mount technology (SMT) design.