An electrical device like this requires a reverse leakage current of 500nA @ 18V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 24V.For operation, diode reaches 1.2V @ 10mA at the maximum voltage - Forward (Vf).
BZX85C24 R0G Features
reverse leakage current of 500nA @ 18V 500nA @ 18V is the maximum voltage (Tol)
BZX85C24 R0G Applications
There are a lot of Taiwan Semiconductor Corporation BZX85C24 R0G applications of zener single diodes.