Torex Semiconductor Europe  has announced the XC9244/45 series of synchronous step-down DC-DC converter ICs which provide high efficiency and a stable power supply with output currents of up to 400mA achievable using only a coil and two ceramic capacitors connected externally.
Available in a tiny USPN-6 (1.3 x 1.3 x 0.4mm) package, the XC9244/45 series features a built-in 0.65 Ohm P-channel driver transistor and 0.45 Ohm N-channel switching transistor.
Minimum operating voltage is 2.3V and output voltage is fixed within a range of 0.8V to 4.0V in 50mV steps (accuracy: ± 2.0%). The XC9244 is PWM control and the XC9245 series is automatic PWM/PFM switching control, providing fast response, low ripple (<10mV) and high efficiency over the full range of load conditions.
The XC9244/XC9245 series has a 0.25ms high speed soft-start for quick turn-on. During standby, all circuits are shutdown to reduce current consumption to as low as 1.0?A or less.