The RP503 from Ricoh Electronic Devices is a DC to DC Converter with Input Voltage 2.5 to 5.5 V, Output Voltage 1 0.8 to 2.5 V, Output Current 1 600 mA, Operating Temperature -40 to 85 Degree C, Storage Temperature -55 to 125 Degree C. Tags: Surface Mount, Buck/Step down. More details for RP503 can be seen below.