This value (Tol) represents the maximum voltage that can be supplied.Zener (Nom) voltage is reduced to 2.2V during operation.This device should be operated with 5mA as the working test voltage.
UDZVTE-172.2B Features
the working test voltage to 5mA minimal dynamic impedance is 5mA
UDZVTE-172.2B Applications
There are a lot of ROHM Semiconductor UDZVTE-172.2B applications of zener single diodes.