I never used this, so am I correctly interpretting this chart fig. 4 on page 7, that if my pulse is 1s long with repetition every 10s, then the thermal impedance will be 40K/W, and if the power dissipated is 1W then the junction will be 40K above ambient?
https://assets.nexperia.com/documents/data-sheet/BCP56_BCX56_BC56PA.pdf
https://assets.nexperia.com/documents/data-sheet/BCP56_BCX56_BC56PA.pdf