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edfas.org ELECTRONIC DEVICE FAILURE ANALYSIS | VOLUME 23 NO. 1 28 FINDING SHORTED COMPONENTS ON PRINTED CIRCUIT BOARDS (continued from page 25) CONCLUSION Short-circuit protection features in switching mode power supplies and step down voltage regulators prevent thermal damage on shorted components. The protection feature keeps some components in a shorted state where applying power frompower inputmay not be able to ener- gize faulted components. This behavior increases the diffi- culty for failure analysis to find the shorted component(s). The IR-based direct current injectionmethod described in this article is designed toaddress the failure characteristics of modern PCBAs. Compared with other localized short-circuit identifi- cation methods such as magnetic field or voltage drop methods, the method described here does not require specialized equipment, it can be applied on complicated multilayer PCBAs, it is very efficient, and does not require multiple components to be measured. The basic steps to perform IR-based direct current in- jection method were described and techniques to ensure the procedure is nondestructive were described. The process to keep the case temperature of shorted components as low as possible while achieving sufficient confidence to confirm faulted components was listed in detail. Finally, an example showed the application and result of IR-based direct current injection method to be an efficient, low-cost, nondestructive method for failure analysis. REFERENCES 1. G.L. Schnable and R.S. Keen: “Failure Mechanisms in Large-Scale Integrated Circuits,” IEEE Trans Electron Devices, 16 (4), April 1969, p. 322-332, doi: 10.1109/T-ED.1969.16752. 2. P. Singh: “Power MOSFET Failure Mechanisms,” INTELEC 2004. 26th Annual International Telecommunications Energy Conference, Chicago,IL,USA,2004,p.499-502,doi:10.1109/INTLEC.2004.1401515. 3. M. Hechtl, G. Steckert, andC. Keller: “Localization of Electrical Shorts in Dies and Packages using Magnetic Microscopy and Lock-in-IR Thermography,” Int. Symp. Phys. Failure Anal. Integr. Circuits, 2006, p. 252-255, doi: 10.1109/IPFA.2006.251041. 4. S. Huang, J. Zeng, H Zhou, Z. Liu, and Y. Zhou: “A PCB Short Circuit Locating Scheme Based on Near Field Magnet Specific Point Detecting,”2015,ComputationalIntelligenceandIntelligentSystems, Vol 575. 5. LeakSeeker, https://www.eds-inc.com/leak.html. 6. J. Xu, J. Li, and Y. Jiang, “Components Locating inPCBFault Diagnosis Based on Infrared Thermal Imaging,” Proc. Int Conf. Inform. Comp. Sci., 2009, p. 7-9, doi: 10.1109/ICIC.2009.109. ABOUT THE AUTHORS Zhifeng Zhu earned his bachelor’s and master’s degrees in materials processing engineering from Shanghai JiaoTong University, China. He joined Rockwell Automation as a reliability engineer in 2007, his latest position is the senior project reliability engineer. In recent years, hemainly focused on developing root cause failure analysis capabilities in Shanghai for various of Rockwell Automation products returned from customers, as well as developing reliability calculation tools. He is an ASQ Certified Reliability Engineer and a certified Six Sigma Green Belt. GarronMorris has 25 years of experience in reliability and thermal manage- ment of power electronics used in industrial electronics and medical imaging systems. As a senior principal engineer at Rockwell Automation, he is focused on developing the next generation of reliablemotor drives, implementing advanced predictive lifemodels, and solving corro- sion issues in power electronics. Morris has bachelor andmaster degrees inmechanical engineering from University of Wisconsin at Milwaukee. He is a certified Design For Six Sigma Master Black Belt, ASQ Certified Reliability Engineer, and recently received the Best Paper award at the IEEE Reliability and Maintainability Symposium. Matching job seekers to employers just got easier with ASM International’s new CareerHub. After logging on to the ASM website, job seekers can upload a resume and do searches on hiring companies for free. Advanced searching allows filtering based on various aspects of electronics, e.g., R&D, manufacturing, or materials. Employers and suppliers can easily post jobs and set up pre-screen criteria to gain access to highly qualified, professional job seekers around the globe. For more information, visit careercenter.asminternational.org. VISIT THE CAREER HUB