An electrical device such as this requires reverse leakage current of 100nA @ 14V.During operation, the maximum voltage - Zener (Nom) is reduced to 20V volts.
BZX584B20 RSG Features
reverse leakage current of 100nA @ 14V 100nA @ 14V is the maximum voltage (Tol)
BZX584B20 RSG Applications
There are a lot of Taiwan Semiconductor Corporation BZX584B20 RSG applications of zener single diodes.