The AAT4290 and AAT4291 SmartSwitch products aremembers of AnalogicTech’s Application Specific PowerMOSFET™ (ASPM™) product family. The AAT4290 andAAT4291 are five and three P-channel MOSFETs, respectively,configured for use as a microprocessor I/O expander.Having independent drain outputs and a commonsource input, they operate with an input voltage rangingfrom 1.8V to 5.5V, making them ideal for 2.5V, 3.3V, or5V systems, as well as systems powered by lithium-ion/polymer batteries. Each switch features a 500ns turn-ontime. The switch states are controlled by AnalogicTech’sSimple Serial Control™ (S2Cwire™) interface which permitsease of control and efficiency of size. The quiescentsupply current is very low, typically 4.5μA. In shutdownmode, the supply current is reduced to less than 1μA.