Prediction of ESL in Discrete Ceramic Capacitors by 3D Modeling with 2D Optical Images

Abstract

The equivalent series inductance (ESL) in discrete ceramic capacitor (CC) deteriorates the bypassing performance for common mode electromagnetic interference (EMI). The ESL in CCs soldered on finished printed circuit board (PCB) is difficult to predict. This paper investigates the relations between the ESL and the component lead length. A 3D modeling technique with 2D optical images is developed, the ESL is predicted by a computational electromagnetic (EM) analysis with the 3D model. The uncertainty in the ESL prediction is less than 1.1 nH in one typical case. The predicted resonant frequencies at around 15 MHz show a discrepancy within 0.11 MHz compared with the vector network analyzer measurement results, the error in the ESL prediction is within 1.5% in the typical case.