Thermal hysteresis and its possible effect in restricting the hot-spot-free operating range of some power transistors

Studies conducted on a number of silicon power transistors indicate that for some devices a hot spot, once formed, will remain even though the power dissipation is reduced to a level at which operation was previously free of hot spots. The hot spot can be eliminated only by a significant reduction in power dissipation from the level at which the hot spot first appeared. The effect of the hot spot on reliable device operation is discussed.