Temperature rise for Figure 2-2 at 48V input voltage, 12V output voltage with 25A load without fan is 98.5⁰C. This picture was taken once the device reached the steady state at room temperature (around 25⁰C).

Figure 2-2 48V_IN, 25A Thermal Image With No Fan

Figure 2-3 and Figure 2-4 are taken with a fan blowing on the board. With an efficient cooling system or with a strong airflow in place, the board can perform a lot better thermally when operating at any load (50A maximum) in a steady-state. Both of the following measurements are also taken at room temperature (around 25⁰C).

Figure 2-3 48V_IN, 25A Thermal Image With Fan

Figure 2-4 48V_IN, 50A Thermal Image With Fan