An electrical device like this requires a reverse leakage current of 5μA @ 1V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 3.9V.For operation, diode reaches 1.2V @ 200mA at the maximum voltage - Forward (Vf).
BZX85C3V9_T50R Features
reverse leakage current of 5μA @ 1V 5μA @ 1V is the maximum voltage (Tol)
BZX85C3V9_T50R Applications
There are a lot of ON Semiconductor BZX85C3V9_T50R applications of zener single diodes.