Conformity Magazine - September 2008 - (Page 54)

o use for testing products. Not all manufacturers have the facilities to construct such a system for testing. The ESDA working group is recommending using two different tests, either an IEC-compliant ESD simulator to simulate the initial fast event, or a transmission line pulser (TLP) to provide the long slow discharge that follows. Both kinds of simulators are available commercially from a number of manufacturers, and will provide an easy to accomplish bench-top test for products with connectors to external cables. Although we’ve been talking about Ethernet cables, the same kind of event occurs from shorter cables as well. The charge will likely be less because of the shorter length of the cable (and lower total cable capacitance), but the effect is the same – a CDE into a port of an electronic product. Possibly the most widely used cables likely to be plugged and un-plugged into a port by a user are USB cables, but any cable capable of holding a charge will cause a CDE to occur. Summary The vast majority of ESD simulators today are ones which are designed to meet the requirements of IEC 61000-4-2, and this will likely be the case into the future. Work being done within the IEC Maintenance Team responsible for the next revision of 61000-4-2 will not be recommending any changes to the basic simulator, but will concentrate instead on clarification (there will be some modifications to the test set-ups to improve reproducibility of tests). Although the automotive industry is moving towards harmonization with IEC standards through ISO standards changes, it isn’t likely that individual corporate standards will go away. Therefore, simulators with special discharge networks and higher voltage capabilities will still be required. MIL-STD 883 isn’t likely to change, and various standards will continue to evolve for testing at the IC level. Overall, the simulators that exist today are pretty much what we’ll see for the next decade for most applications. However, if the TLP testers can be improved for testing devices to standards, such as IEC 61000-4-2, it’s possible these could become the ESD simulator of the future, offering more highly controlled discharge, and better reproducibility and repeatability. Michael Hopkins is an independent consultant to Thermo Fisher Scientific, and can be reached at michael.hopkins@thermofisher.com. Notes 1. A simulator manufactured by Andy Hish was widely used by electronic manufacturers in the 1980’s and became a defacto standard for many. The KeyTek Model 2000 gun was introduced in 1983 which in addition to providing a range of discharge modules to meet the various ESD standards requirements, also was the first ESD simulator to provide a method of testing for the individual effects electric and magnetic fields generated by ESD events. One of the earliest testers was manufactured by Hartley, a UK company, and distributed by KeyTek Instrument Corp in the early ‘80’s. KeyTek developed the first completely computer controlled tester for IC’s in 1989 called the “ZapMaster.” Prior to the publication of the EMC Directive, each country had it’s own requirements for EMC compliance and outside manufacturers wishing to do business in Europe were faced with a volumes of different compliance requirements. KeyTek (now part of Thermo Fisher Scientific) and Schaffner (now Teseq) were the dominant suppliers of ESD simulators for IEC harmonized standards, followed by Haefely, EMTest, EMCPartner, Noise Ken, Kikisui and others. Technical Tidbit – Cable Effects Part 1: Cable Discharge Events; Doug Smith, January 2002. Cable Discharge Event in the Local Area Network: Intel White Paper July 2001; order Number 249812-001. A Simple Model For a “Cable Discharge Event”; Rick Brooks; IEEE802.3 Cable Discharge Ad-hoc, March 2001. 2. Your online source for product & service providers that will help your business grow 3. Conformity Online Buyer’s Guide Testing and Certification EMI/RFI Shielding Passive Electronic Certification Education and Professional Training & Resources Test, Measurement and Monitoring Equipment Cabinets, Racks & Enclosures Chambers, Shielding and Accessories plus more Connecting Buyers and Sellers ® 4. 5. 6. 7. 8. www.conformitydirectory.com 54 Conformity September 2008 FAST Link www.conformity.com/2170 http://www.conformitydirectory.com http://www.conformitydirectory.com http://www.conformity.com/2170

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Conformity Magazine - September 2008 Contents Editor’s Note Commission Adopts Regulations for Internet-Based TRS Services Another Company Fined for Non-Compliance with HAC Requirements FCC Extends “Do-Not-Call” Registry Compliance Requirements Marketing Company Gets $1.4 Million Fine for Junk Faxes EU Commission Codifies Directive on TTE Market Competition EU Commission Releases Updated Standards List for the R&TTE Directive Updated Standards List for the “New” Low Voltage Directive Released New Standards List Released for the EU’s Machinery Directive The ESD Association: Voluntary Standards in Action ESD Open Forum Medical EMC Standards: Towards the 4th Edition of IEC 60601-1-2 iNARTE Informer Pre-Pulse Voltage in the HBM ESD Model Digital Interfaces and EMC Performance ESD Design Buyer’s Guide Product News Commission Publishes Updated Standards List for the EU’s Personal Protective Equipment Directive FDA Links “Human Factors” to Adverse Events with Medical Devices CPSC Actions in the News IEC Standards Update UL Standards Update Product Reviews Telcordia Standards Update From Our “You Can’t Make This Stuff Up” Department Looking Back: Items from Past Issues of Conformity Advertisers

Conformity Magazine - September 2008

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