An electrical device like this requires a reverse leakage current of 500nA @ 136.8V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 180V.
2M180ZHA0G Features
reverse leakage current of 500nA @ 136.8V 500nA @ 136.8V is the maximum voltage (Tol)
2M180ZHA0G Applications
There are a lot of Taiwan Semiconductor Corporation 2M180ZHA0G applications of zener single diodes.