RT9261/RT9261A pdf datasheet (

The RT9261 Series are VFM Step-up DC/DC ICs with ultra
low supply current by CMOS process and suitable for
use with battery-powered instruments.
The RT9261 IC consists of an oscillator, a VFM control
circuit, a driver transistor (LX switch), a reference voltage
unit, an error amplifier, resistors for voltage detection, and
a LX switch protection circuit. A low ripple and high
efficiency step-up DC/DC converter can be constructed of
this RT9261 IC with only three external components.
The RT9261A IC provides with a drive pin (EXT) for an
external transistor, so that a power transistor can be
externally applied. Therefore, the RT9261A IC is
recommended for applications where large currents are
required. EN pin enables circuit to set the standby supply
current at a maximum of 0.5uA.