In summary, TransGuards™ are multilayer zinc oxide devices that act as bi-directional zeners in the ON state and like an X7R capacitor in the OFF state. When choosing the proper device, the designer must consider the maximum operating voltage, the energy rating of the expected transient, and circuit capacitance. Additionally, TransGuards™ can be retrofitted in existing designs that use SMT EMC capacitors in conjunction to bi-directional diodes with the possible benefit of saving board space and overall component cost.