An electrical device like this requires a reverse leakage current of 45nA @ 25V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 33V.
UDZS33B R9G Features
reverse leakage current of 45nA @ 25V 45nA @ 25V is the maximum voltage (Tol)
UDZS33B R9G Applications
There are a lot of Taiwan Semiconductor Corporation UDZS33B R9G applications of zener single diodes.