The reverse leakage current needed to power this electric device is 45nA @ 21V.As part of the operation, the maximum voltage - Zener (Nom) is reduced to 27V.
UDZS27B R9G Features
reverse leakage current of 45nA @ 21V 45nA @ 21V is the maximum voltage (Tol)
UDZS27B R9G Applications
There are a lot of Taiwan Semiconductor Corporation UDZS27B R9G applications of zener single diodes.