The ST1S15 from STMicroelectronics is a DC to DC Converter with Input Voltage 2.3 to 5.5 V, Output Voltage 1 1.82 to 2.8 V, Output Current 1 500 mA, Operating Temperature -40 to 125 Degree C. Tags: Surface Mount, Buck/Step down. More details for ST1S15 can be seen below.