The LTC 1477/LTC1478 protected high side switches provide extremely low RDS(ON) switching with built-in protection against short-circuit and thermal overload conditions. A built-in charge pump generates gate drive higher than the supply voltage to fully enhance the internal NMOS switch. This switch has no parasitic body diode and therefore no current flows through the switch when it is turned off and the output is forced above the input supply voltage. (DMOS switches have parasitic body diodes that become forward biased under these conditions.) Two levels of protection are provided by the LTC1477/LTC1478. The first level of protection is shortcircuit current limit which is set at 2A. The short-circuit current can be reduced to as low as 0.85A by disconnecting portions of the power device (see Applications Information). The second level of protection is provided by thermal overload protection which limits the die temperature to approximately 130C.