This part is a kind of semiconductor called AIC2304.

Function of this product has PWM Step-Down DC/DC Converter.

Manufacturers : Analog Intergrations Corporation

Image and pinout :

Some of the text within the PDF file :

AIC2304 1A Synchronous PWM Step-Down DC/DC Converter  FEATURES  2.5V to 5.5V Input Voltage Range  1.0A Guaranteed Output Current  Up to 95% Efficiency  Low RDS(ON) Internal Switche: 280mΩ  No Schottky Diode Required  100% Duty Cycle in Low Dropout Operation  Operating Frequency: 1.5MHz  Accurate Reference 0.6V Provides Low Output Voltages  APPLICATIONS  LCD TV  Multi-function Peripheral  Cellular Phones  CPU I/O Supplies  Cordless Phones  PDAs and Handy-Terminals  Battery-Operated Devices (1 Li-Ion or 3 NiMH/ NiCd)  APPLICATIONS CIRCUIT  DESCRIPTION The AIC2304 is a low-noise, pulse-widthmodulated (PWM), DC-DC step-down converter. The device is available in an adjustable version and fixed output voltages of 1.0V, 1.2V, 1.8V, and [ ... ]

AIC2304 PDF Datasheet Download