An electrical device like this requires a reverse leakage current of 3μA @ 1.5V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 5.6V.For operation, diode reaches 1.1V @ 200mA at the maximum voltage - Forward (Vf).
1N5994A Features
reverse leakage current of 3μA @ 1.5V 3μA @ 1.5V is the maximum voltage (Tol)
1N5994A Applications
There are a lot of Microsemi Corporation 1N5994A applications of zener single diodes.