An electrical device like this requires a reverse leakage current of 10μA @ 20V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 28V.For operation, diode reaches 950mV @ 1A at the maximum voltage - Forward (Vf).
SJPZ-K28V Features
reverse leakage current of 10μA @ 20V 10μA @ 20V is the maximum voltage (Tol)
SJPZ-K28V Applications
There are a lot of Sanken SJPZ-K28V applications of zener single diodes.