Idealized model for charged device electrostatic discharge

An analysis is presented for a two-conductor problem in which the source conductor, a sphere with either constant charge or constant potential, approaches a ground plane. Capacitance coefficients are calculated; body potentials, energies, and charges are compared for typical geometries using the two models. In real charged device model events, the device potential and probability of discharge are a function of the charge on the device, its size, and position relative to a ground plane. Proposed test methods specify the potential of the device; the resulting charge on the device and the energy dissipated in the discharge can be lower compared to the actual event. Results are also presented which show the effect of the variation in the impedance elements of the discharge path on the peak value and rise time of the discharge current.