Conformity Magazine- May 2008 - (Page 18) Who Uses Standards and Why? Who uses ESD standards? The list is quite broad, and includes manufacturers, purchasers, and users of ESD-sensitive devices and products; manufacturers and distributors of ESD control products; certification registrars; and third-party testers of ESD control products. Why use ESD standards? The reasons are numerous: • They help ensure consistency of the reported susceptibility of ESD sensitive products; • They help ensure consistency of ESD control products and services; • They provide a means of objective evaluation and comparison among competitive ESD control products; • They help reduce conflicts between users and suppliers of ESD control products; • They help in developing, implementing, auditing, and certifying ESD control programs; • They help reduce confusion in the marketplace; In the United States, the use of ESD standards continues to be voluntary; however, their use can be written into contracts or purchasing agreements between buyers and sellers. In much of the rest of the world, the use of standards, where they exist, is compulsory. General Types of Standards As recently as 1990, there were relatively few reliable ESD standards, and many of them were developed for applications other than electronics. In this new century, the landscape has changed significantly with an increasing number of ESD standards developed specifically for the electronics industry. ESD Association standards can be categorized into four main groups. First, there are those that provide ESD program guidance or requirements, such as ANSI/ESD S20.20-2007, Protection of Electrical and Electronic Parts, Assemblies and Equipment (Excluding Electrically Initiated Explosive Devices); ANSI/ESD S6.1-2005, Grounding—Recommended Practice; and ANSI/ESD S1.1-2006, Wrist Straps. These documents are classified as standards, as they all have specific requirements that must be met. The second type of document is called a standard test method. These documents contain procedures that can be used to evaluate device sensitivity or ESD control products, materials, or processes. The procedures called out in a standard test method should provide reproducible test results when tested by two separate labs. Standard test methods include documents such as the recently revised ANSI/ESD STM5.1-2007, Human Body Model (HBM)—Component Level; and ANSI/ESD STM11.13-200, Two Point Resistance Measurement. The third type of document is called a standard practice. A standard practice contains content similar to those found in a standard test method, with one difference: the procedure is not sufficiently developed to ensure that two labs will get the same result when the procedure is followed. In many cases, a document is released as a standard practice so that industry can start to use it. The working group that issued the standard practice continues their efforts to make the test method repeatable and reproducible, with the goal of eventually elevating the document to a standard test method. Finally, the fourth category of standards documents includes advisories and technical reports. These documents are used to provide educational information to potential users. A good example is the ESD Handbook, TR20.20. This document is a companion publication to ANSI/ESD S20.20, and provides detailed, background information on the requirements of the standard, as well as a wealth of information on ESD control issues. Who Are the Primary Standards Developers? Although there are a number of organizations such as IEST, IDEMA and JEDEC involved in ESD standards development, the ESD Association has become the focal point for the development of ESD standards in recent years. As an ANSIaccredited standards development organization, the ESD Association is charged with the development of ESD standards and test methods. The Association also represents the United States on the International Electrotechnical Commission’s ESD Association Advisory documents are not standards but provide general information for the industry or additional information to aid in better understanding the Association’s standards. ESD ADV1.0-2004, Glossary of Terms Definitions and explanations of various terms used in Association Standards and documents are covered in this Advisory. It also includes other terms commonly used in the electronics industry. ESD ADV11.2-1995, Triboelectric Charge Accumulation Testing The complex phenomenon of triboelectric charging is discussed in this Advisory. It covers the theory and effects of tribocharging. It reviews procedures and problems associated with various test methods that are often used to evaluate triboelectrification characteristics. ESD ADV53.1-1995, ESD Protective Workstations This advisory document defines the minimum requirements for a basic ESD protective workstation used in ESD sensitive areas. It provides a test method for evaluating and monitoring workstations. Table 3: ESD Association Advisory Documents 18 Conformity mAy 2008
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