Development of ZnO Varistors Used for Overvoltage Protection of Integrated Circuits

In order to make lower voltage varistors used for overvoltage protection in integrated circuit, based on the proportioning of middle voltage ZnO varistors, study and experiment were done. Lower voltage varistors have been developed by adding grain promoters of TiO2 and crystallons, applying grain boundary stabilizers of B-Ag glass and Ta2O5, using lower sintering temperature and so on. Obtained results indicate that the varistors have lower varistor voltage of 15~ 25 V, little leakage current (2 μA) and outstanding nonlinear I-V characteristics (α 29).