The Effect of Electrical Fast Transients on Multilayer Ceramic Capacitors

This paper investigates the susceptibility of multilayer ceramic (MLC) capacitors to high-voltage electrical fast transients (EFTs). X7R and NP0 MLC capacitors with a 50 V voltage rating and 0603 package size were tested. X7R capacitors often failed during a spike in the voltage, but exhibited no obvious degradation in the measured insulation resistance at low voltages immediately after the failure. NP0 capacitors usually failed by suddenly shorting and maintaining the short after the failure. With the application of additional voltage spikes, some X7R capacitors exhibited a full recovery in terms of the measured resistance, returning to their initial state. The resistance of an X7R capacitor damaged by an EFT event is a function of the applied voltage. The terminal impedance can be modeled as two diodes in parallel.