Influence of a ground plane on the ESD event in electronic systems

Capacitance coefficients were measured for a basic two-conductor system, simulating the approach of a charged object (the human body) to a second object which can be floating or grounded (the equipment under test). Parameters studied include the size of the conductors, their separation, and position relative to vertical and horizontal ground planes. System equations, based on Maxwell´s technique, are solved to yield the body potentials and a relative probability of discharge for the various configurations. The presence of ground planes is shown to increase the ESD (electrostatic discharge) susceptibility of small floating bodies. The results provide a better understanding to the ESD event and demonstrate the importance of ground planes in electrostatic discharge test methods