The AAT4291 SmartSwitchTM is a member of AnalogicTech's Application Specific Power MOSFETTM (ASPMTM) product family. The AAT4291 has three P-channel MOSFETs configured for use as a microprocessor I/O expander. Having independent drain outputs and a common input, the AAT4291 operates with an input voltage ranging from 1.8V to 5.5V, making it ideal for 2.5V, 3.3V, or 5V systems, as well as systems powered by lithium-ion/polymer batteries. Each switch features a fast 500ns turn-