An electrical device like this requires a reverse leakage current of 100nA @ 15V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 19.955V.
CDZFHT2RA20B Features
reverse leakage current of 100nA @ 15V 100nA @ 15V is the maximum voltage (Tol)
CDZFHT2RA20B Applications
There are a lot of ROHM Semiconductor CDZFHT2RA20B applications of zener single diodes.