An electrical device like this requires a reverse leakage current of 80μA @ 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).
3EZ3.9D5/TR12 Features
reverse leakage current of 80μA @ 1V 80μA @ 1V is the maximum voltage (Tol)
3EZ3.9D5/TR12 Applications
There are a lot of Microsemi Corporation 3EZ3.9D5/TR12 applications of zener single diodes.