Various semiconductor technologies such as CMOS technology are particularly vulnerable to electrostatic discharge( ESD). Various models have therefore been developed for simulation and ESD testing: The Human Body Model (HMB), the Machine Model( MM) and the Charged Device Model (CDM).
The Charged Device Model is a model that simulates the discharge of electrostatically charged devices via one or more connections toground. This model can be used to test the sensitivity of circuits to electrostatic discharges. The ESD Association( ESDA) has divided the voltage sensitivities for the Charged Device Model into several classes.