An electrical device like this requires a reverse leakage current of 1μA @ 43V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 56V.For operation, diode reaches 1.2V @ 200mA at the maximum voltage - Forward (Vf).
BZD27B56P-E3-18 Features
reverse leakage current of 1μA @ 43V 1μA @ 43V is the maximum voltage (Tol)
BZD27B56P-E3-18 Applications
There are a lot of Vishay Semiconductor Diodes Division BZD27B56P-E3-18 applications of zener single diodes.