Common-mode rejection ratio characterisation of a broadband electro-optical differential ESD voltage probe

摘要

The concept of an isolated differential voltage measurement system is presented. The proposed probe circuit is designed for broadband measurement of electrostatic discharge (ESD) waveforms. The electro-optical conversion of the measured signal allows the system to operate in an electromagnetically polluted environment. The signal capture and signal processing stages of the system arc separated. Characteristics of the system in terms of differential-mode and common-mode signal sensing are discussed. The common-mode rejection ratio (CMRR) of the system is explored in the gigahertz frequency range. Given the low cost; the system can be implemented both as a standalone probe or as a part of an integrated circuit characterisation and test environment.