High Voltage Solid-State Switches

High voltage and pulsed power applications imply always a certain risk of sparking and flash over by nature, especially if the ambient conditions, operating conditions, or load conditions change unexpectedly. Therefore, the peak current capability of a solid-state switch should be always as high as possible, at the very least higher than the possible short circuit current of the application. Regarding the selection of voltage rating we suggest a safety margin of at least 5 % for MOSFET switches and at least 20 % for all bipolar switches (IGBT, MCT, SCR) to minimize the risk of damage by unexpected voltage fluctuation or unexpected flyback-voltage. The long-term reliabillty, respectively, the Mean Time Between Failures (MTBF) of a high voltage solid-state switch is always a function of its operating temperature. Therefore, we highly recommend operating the switches only at moderate temperatures whenever possible. This is achieved primarily by choosing sufficient on-resistance, current capability, natural capacitance and coupling capacitance. Please refer to the data sheets and the following product surveys for further information.