5% is the maximum voltage (Tol) that can be supplied.Zener single diode is important to note that during operation, the maximum voltage - Zener (Nom) is reduced to 19.2V.Zener single diode reaches 1.92mV/°C when the voltage (Temp Coeff) reaches maximum.
1N4925A Features
1N4925A Applications
There are a lot of Microsemi Corporation 1N4925A applications of zener single diodes.