TPS1H100-Q1: max junction temperature calculation in function of driving time

Hi team, 

If my customer calculates the max junction temperature for their application with a constant current, they are above the maximum temperature. They would like to know how this can be calculated in function of the “driving” time?

Their specs are as follws:

Imax: 5A (no high side limitation)

Tmax: 50 or 100ms

Rdson_max: 166mOhm

Ta max: 85°C

Roja: 35 °C/W @100mm2 4layers

Tshutdown: 175°C

Worst case junction temperature

Do you have any suggestion?

Thanks for the help. 

Obinna.