The STS521050B181AH from Eaton is a Power Diode with Reverse Current 0.1 µA, Reverse Voltage 5 V, Temperature operating range -55 to 150 Degree C, Reverse Breakdown Voltage 5.5 to 8.5 V, Total Capacitance 18 to 20 pF. Tags: Surface Mount. More details for STS521050B181AH can be seen below.