This part is a kind of semiconductor called SY8009A.

Function of this product has (SY8009A/B) Synchronous Step Down Regulator.

Manufacturers : Silergy

Image and pinout :

Some of the text within the PDF file :

SY8009A/SY8009B High Efficiency 1.5MHz/1MHz, 1.5A/2A Synchronous Step Down Regulator General Description The SY8009A and SY8009B are high-efficiency, high frequency synchronous step-down DC-DC regulator ICs capable of delivering up to 1.5A/2A output currents. The SY8009 family operate over a wide input voltage range from 3V to 5.5V and integrate main switch and synchronous switch with very low RDS(ON) to minimize the conduction loss. Low output voltage ripple and small external inductor and capacitor sizes are achieved with greater than 1MHz switching frequency. Features • Low RDS(ON) for internal switches (top/bottom) • SY8009A: 180mΩ/120mΩ, 1.5A, SOT23-5 • SY8009B:100mΩ/80mΩ,2.0A SOT23-6, SSOT23-6 • 3-5.5V input voltage range • High switching frequency minimizes the ex [ ... ]

SY8009A PDF Datasheet Download