IEC 61188-6-2:2021 pdf download

IEC 61188-6-2:2021 pdf download.Circuit boards and circuit board assemblies – Design and use – Part 6-2: Land pattern design
1 Scope
This part of IEC 61188 describes the requirements of design and use for soldering surfaces of land pattern on circuit boards. This document includes land pattern for surface mounted components. These requirements are based on the solder joint requirements of IEC 61191-2:2017.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60194-2, Printed boards design, manufacture and assembly – Vocabulary – Part 2: Common usage in electronic technologies as well as printed board and electronic assembly technologies IEC 61188-6-1, Circuit boards and circuit board assemblies – Design and use – Part 6-1: Land pattern design – Generic requirements for land pattern on circuit boards IEC 61188-6-4, Printed boards and printed board assemblies – Design and use – Part 6-4: Land pattern design – Generic requirements for dimensional drawings of surface mounted components (SMD) from the viewpoint of land pattern design IEC 61191-2:2017, Printed board assemblies – Part 2: Sectional specification – Requirements for surface mount soldered assemblies
5 Land pattern determination
This standard discusses the following method of providing information on land patterns. For each typical termination type, one land pattern for one termination will be determined by formulas based on the termination dimensions (nominal value).The assumption is that the following dimensions have the necessary and sufficient accuracy: a) component tolerance; c) printed board fabrication tolerance; d) placement tolerance. NOTE Further information on the effect of the above dimensional tolerance on the land pattern can be found in Annex A of IEC 61188-6-1:2021. There are two classes of land pattern relating to the assembly limitations of components and the intended soldering process: • land pattern for wave soldering – For low density product applications, land patterns are designed to accommodate several types of wave soldering applicable to surface mounted components. • land pattern for reflow soldering – The land patterns generated for all device families shall provide a robust solder attachment condition for reflow soldering.
6 Requirements
6.1 General requirements The calculated land pattern geometry for an electronic component can be different depending upon the type of soldering process to be used. Wherever possible, land patterns should be defined in such a manner that are transparent to the attachment process being used. Land pattern designers can use the information contained herein to establish standard configurations not only for manual designs but also for computer-aided design systems. Whether parts are mounted on one side or both sides of the board, subjected to wave soldering, reflow soldering, or other type of soldering, the land pattern and part dimensions should be optimized to insure proper solder joint and inspection criteria. Although patterns are dimensionally defined and since they are a part of the circuit board geometry, they are subject to the reducibility levels and tolerances associated with plating, etching, assembly or other conditioning process. The producibility aspects also pertain to the use of solder mask and the registration required between the solder mask and the conductor patterns.A correctly designed land pattern is essential to satisfy quality standards such as IEC 61191- 2:2017, which specifies generic requirements for the concept of land pattern design. The land pattern designer should design in accordance with the concept in this document, and they could adopt appropriate numeric values that were suitable for their purpose. The numeric values described in this document are the parameters that were selected as references to show the concept of land-pattern design.