Report Addresses Fires Attributable to Lithium Batteries

As part of an effort to reduce the risk of fires caused by lithium batteries in waste electrical and electronic equipment (WEEE), a consortium of industry groups has just issued a report that compiles a number of “good practices” applicable to all phases of the product development process.

The report, “Recommendations for Tackling Fires Caused by Lithium Batteries in WEEE,” compiles the findings…

DILBERT © 2021 Scott Adams. Used By permission of ANDREWS MCMEEL SYNDICATION. All rights reserved.

Toward Standardization of Low Impedance Contact CDM

By Nathan Jack, Brett Carn, and Josh Morris

Introduction

The field-induced Charged Device Model (CDM) test method standardized in ANSI/ESDA/JEDEC JS-002 [1] is widely used for CDM qualification of integrated circuits. Because it relies on an air spark to initiate the stress, the pulse amplitude varies from zap to zap [2]. This discharge variation is increasingly significant as pre-charge voltage V_pre decreases [3].

Relay-based alternatives have been proposed to eliminate the variable air spark [2], [4]. Such “contact CDM” (CCDM) systems rely on transmission line pulsing and utilize 50 Ω coaxial cables and relays. It has been shown that 50 Ω systems generate pulses much wider than those of JS-002, but a better match can be obtained using lower system impedances. In [3], CCDM systems of 50 Ω, 25 Ω, and 11 Ω impedances were demonstrated. It was theorized that a 16.6 Ω CCDM system would provide the closest match to JS-002 in terms of waveform shape and the failure current (I_fail) thresholds generated.

Dear colleagues, friends, and ESD enthusiasts,

On behalf of EOS/ESD Association, Inc. and the 2021 Symposium Steering Committee, it is my honor to welcome you to the proceedings of the 43rd Annual EOS/ESD Symposium and Exhibits at The Westin La Paloma Resort & Spa in Tucson, Arizona. The EOS/ESD Symposium represents the world’s leading forum on Electrostatic Discharge and Overstress. Although COVID-19 is still impacting our business and operations significantly, the Steering Committee and the Technical Program Committee, with all our great volunteers, spared no effort to ensure that the 43rd Symposium is a great experience for all attendees, on-site or virtually online.

In the 43rd EOS/ESD Symposium, the Steering Committee and the Symposium Strategy Team have structured the program in five focus areas, each with a program of 1-1.5 days. The focus areas are Advanced Technologies and Device Testing, Automotive, Communications, Mixed Voltage Applications, and, as in the last years, EMC. Each focus area comprises one or several sessions with technical papers, invited talks, tutorials, seminars, and workshops. For the first time, the Symposium started on Monday and was, therefore, one day longer than in the past, allowing more time for program and discussion. In parallel, for the fifth time, the “Manufacturing Track” offers full 3.5 days of technical sessions, hands-on sessions, workshops, discussion groups, and technology showcases in the field of EOS/ESD in manufacturing – control materials, technologies, and techniques.

Industry Council Survey on Latch-up: A Brief Status Update

By Theo Smedes (NXP Semiconductors) for the Industry Council on ESD Target Levels

In July 2020, the Industry Council on ESD Target levels, in collaboration with the JEDEC JESD78 working group, launched a survey on Latch-up testing. An earlier article¹ in this magazine described the reasons for launching the survey and invited representatives from the industry to participate in order to collect data and opinions. The survey is now closed, but a full pdf version of the survey² is still available online. This article will give a short update on the results of the response analysis that is ongoing.

The Industry Council received 70 individual responses, from at least 35 companies from more than 16 countries. Multiple responses per company were encouraged because of the wide diversity of products, customers, and requirements. Although the survey was oriented at Revision E of the JESD78 standard, it is, of course, relevant to know which standards are actually used. The responses show that although other test standards and older JESD78 revisions are also used, the most prevalent standard in use is JESD78E. This gives good confidence in the relevance of the responses with respect to the survey’s goals.

Static Control Flooring in High Reliability Environments

Special Considerations for Static Control Flooring for Added Risk Reduction

By Tom Ricciardelli

tatic control flooring is widely used throughout the electronics industry to provide a means to ground personnel and mobile equipment to control static charge generation and build-up. While I’d argue that it is always important to control static in an electronics manufacturing environment, there are some organizations where the risk of a device failure could have more serious consequences. This raises the bar in terms of managing the risk of failure and there are some things you should keep in mind when choosing static protective flooring to help with that.

What is High Reliability?

A group of researchers at the University of California, Berkeley, in their research to understand causes of major failures, identified certain organizations that were better at handling and avoiding these failures. ^1,2  In their work, they defined a high reliability organization (HRO) as “an organization that has succeeded in avoiding catastrophes in an environment where normal accidents can be expected due to risk factors and complexity.” They further defined the five principles that HROs have in common:

System-Level Grounding

Is Your System Well Grounded? Consider These Points in Effective Grounding

By Vladimir Kraz

rounding is the most fundamental property of all types of electrical equipment. There are plenty of quality articles on specific subjects in In Compliance Magazine and in other publications, largely on grounding on a printed circuit board (PCB) level. This article focuses on a path less traveled, grounding on a system level, that is grounding of the equipment in actual use at the factories.

There are several key aspects of grounding, including safety, ESD, EMI, and signal integrity. While this and other magazines have published detailed articles on one or more of these subjects, this article combines them all to assist equipment users and tool makers in understanding what is important and how to achieve optimal ground performance. This article does not cover PCB grounding (there are plenty of excellent articles on this subject) and portable tools with double insulation that do not have grounding.

Caster Contact:
The Achilles Heel of ESD Floors

Standard ESD Resistance Tests Do Not Fully Evaluate a Floor’s Suitability for Grounding Carts, Chairs, and Mobile Workstations

By David Long

hat’s the purpose of installing an ESD floor? The most common answer to this question is “we need ESD flooring to prevent static charges on mobile personnel when they handle static sensitive parts and systems.” In other words, we need the effectiveness of a wrist strap, but we don’t want to deal with the restrictions of wires and cords.

While this answer highlights a key attribute of a properly functioning ESD floor, it sets the bar very low. It also short sells the many advantages an ESD floor actually offers. Like every other static mitigation component, ESD flooring is only one piece of a larger comprehensive system that keeps all parts, machines, tools, packaging, work surfaces, and personnel at the same potential.

When floors are evaluated, specifiers focus on two main performance parameters: 1) the flooring system’s electrical resistance; and 2) how much charge a person can develop when walking on the floor wearing specific footwear. But what about the parts themselves? How do we protect them? When we move parts from one operation to another, we don’t cradle them in the palm of our hands. We move parts and systems in zip lock bags, on wheeled carts with trays, and possibly with automatically guided vehicles. In agile manufacturing operations, the ESD floor might even be used as the primary ground for workbenches on wheels.

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