An electrical device like this requires a reverse leakage current of 100μA @ 1V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 3.3V.For operation, diode reaches 1.2V @ 200mA at the maximum voltage - Forward (Vf).
1N3821 Features
reverse leakage current of 100μA @ 1V 100μA @ 1V is the maximum voltage (Tol)
1N3821 Applications
There are a lot of Microsemi Corporation 1N3821 applications of zener single diodes.