The RT9261 Series are VFM Step-up DC/DC ICs with ultralow supply current by CMOS process and suitable foruse with battery-powered instruments.The RT9261 IC consists of an oscillator, a VFM controlcircuit, a driver transistor (LX switch), a reference voltageunit, an error amplifier, resistors for voltage detection, anda LX switch protection circuit. A low ripple and highefficiency step-up DC/DC converter can be constructed ofthis RT9261 IC with only three external components.The RT9261A IC provides with a drive pin (EXT) for anexternal transistor, so that a power transistor can beexternally applied. Therefore, the RT9261A IC isrecommended for applications where large currents arerequired. EN pin enables circuit to set the standby supplycurrent at a maximum of 0.5uA.