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LTC1478 - Single and Dual Protected High Side Switches

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 short-circuit 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 130°C. The LTC1477 single is available in 8-lead SO packaging. The LTC1478 dual is available in 16-lead SO packaging.

Features Extremely Low RDS(ON) Switch: 0.07 ohms No Parasitic Body Diode Built-In Short-Circuit Protection: 2A Built-In Thermal Overload Protection Operates from 2.7V to 5.5V Inrush Current Limited Ultralow Standby Current: 0.01µA Built-In Charge Pump Controlled Rise and Fall Times: tR = 1ms Dual Switch in Narrow 16-Pin SO Package Typical Application

Applications Notebook Computer Power Management Power Supply/Load Protection Supply/Battery Switch-Over Circuits Circuit Breaker Function Peripheral Power Protection Reconstruction Filters Packaging