Can we use the TPS7H2221-SEP when the input voltage is 5.45V?

The maximum voltage of TPS7H2221-SEP is 6V. 

So If we apply the derating rule, we can use this switch until +5.4V. 

- Linear voltage regulator = Vin * 90%

Should we consider the derating rule based on the ECSS standards?

- Linear voltage regulator = Vin * 90%

ECSS-Q-ST-30-11C Rev.2: Derating – EEE components (23 June 2021)