The ST1S03 from STMicroelectronics is a DC to DC Converter with Input Voltage 2.7 to 16 V, Output Voltage 1 0.8 to 5 V, Output Current 1 1500 mA, Operating Temperature 150 Degree C, Storage Temperature -25 to 150 Degree C. Tags: Surface Mount, Buck/Step down. More details for ST1S03 can be seen below.