Quote Originally Posted by irving2008 View Post
You are indeed correct, however there is a world of difference between a pulse width modulated motor controller with a high peak current but low RMS value and a linear regulator with a constant high dissipation.
You missed my point. The motor controller has to dissipate the heat caused by the voltage loss of the high and low side Vsat. A loss of 2V at 15A is 30 watts of heat to dissipate per IC (there's 2 on the board), a total of 60 watts with no heatsink. The movement of the air across the surface of the IC and the PCB is able to dissipate the 60 watts.

Eddy