It is necessary to supply this electrical device with a reverse leakage current of 100nA @ 18V.A voltage of 2% indicates the maximum voltage (Tol) that can be supplied.If you want this device to work properly, you should set the peak reverse voltage to 100nA.
MMSZ5252C-G3-18 Features
reverse leakage current of 100nA @ 18V 100nA @ 18V is the maximum voltage (Tol)
MMSZ5252C-G3-18 Applications
There are a lot of Vishay Semiconductor Diodes Division MMSZ5252C-G3-18 applications of zener single diodes.