The 3813-S3.3 from Modular Devices is a DC to DC Converter with Input Voltage 18 to 50 V, Output Voltage 1 3.1 to 3.4 V, Output Current 1 0.5 to 5 A, Output Power 16500 mW, Isolation Voltage 500 Vdc. Tags: Through Hole. More details for 3813-S3.3 can be seen below.