Detection and Reliability Risks of Counterfeit Electrolytic Capacitors

Abstract

Counterfeit electronics have been reported in a wide range of products, including computers, medical equipment, automobiles, avionics, and military systems. Counterfeiting is a growing concern for original equipment manufacturers (OEMs) in the electronics industry. Even inexpensive passive components such as capacitors and resistors are frequently found to be counterfeit, and their incorporation into electronic assemblies can cause early failures with potentially serious economic and safety implications. This study examines counterfeit electrolytic capacitors that were unknowingly assembled in power supplies used in medical devices, and then failed in the field. Upon analysis, the counterfeit components were identified, and their reliability relative to genuine parts was assessed. This paper presents an offline reliability assessment methodology and a systematic counterfeit detection methodology for electrolytic capacitors, which include optical inspection, X-Ray examination, weight measurement, electrical parameter measurement over temperature, and chemical characterization of the electrolyte using Fourier Transform Infrared Spectroscopy (FTIR) to assess the failure modes, mechanisms, and reliability risks. FTIR was successfully able to detect a lower concentration of ethylene glycol in the counterfeit capacitor electrolyte. In the electrical properties measurement, the distribution of values at room temperature was broader for counterfeit parts than for the authentic parts, and some electrical parameters at the maximum and minimum rated temperatures were out of specifications. These techniques, particularly FTIR analysis of the electrolyte and electrical measurements at the lowest and highest rated temperature, can be very effective to screen for counterfeit electrolytic capacitors.