TPS54335-1A: TPS54335-1ADRCR Operating temperature

Hello

          We have  developing industrial products with TPS54335-1ADRCR for a long time， and found in the data that Tj of IC is 150 degree。The recent design is 12V to 3.3V with current 1A MAX,and operating air temperature is 100°C MAX,so we think TPS54335-1ADRCR can work well. 

          While we found in the datasheet,TPS54335-1ADRCR  can only work winthin 85°C.So is this data serious? We want to know  what conditions restrict the use of this chip。If it's just a matter of heat dissipation, we believe there's no problem because the heat dissipation of this case is tiny.

        Thank you so much!