An electrical device like this requires a reverse leakage current of 100nA @ 17V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 22V.For operation, diode reaches 900mV @ 10mA at the maximum voltage - Forward (Vf).
SZMMSZ5251ET1G Features
reverse leakage current of 100nA @ 17V 100nA @ 17V is the maximum voltage (Tol)
SZMMSZ5251ET1G Applications
There are a lot of ON Semiconductor SZMMSZ5251ET1G applications of zener single diodes.