An electrical device like this requires a reverse leakage current of 100nA @ 28V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 39V.For operation, diode reaches 1V @ 100mA at the maximum voltage - Forward (Vf).
BZV55B39 L0G Features
reverse leakage current of 100nA @ 28V 100nA @ 28V is the maximum voltage (Tol)
BZV55B39 L0G Applications
There are a lot of Taiwan Semiconductor Corporation BZV55B39 L0G applications of zener single diodes.