The B0505S-1W is a DC-DC switching converter with input/output isolation. Input and Output voltage is identical, but the input circuit is electrically isolated from the output circuit.
These devices are very helpful for example in power supplies for audio applications, where ground loops can cause unwanted side effects like hum/ripple.
Please see the pictures for the pinout.
Input voltage: 4.5-5.5V
Output voltage: 5V, 200mA
Output peak current: 220mA
Switching frequency: 100kHz
Isolation voltage: 1600V DC (max. 1 minute)
Isolation resistance: 1 Gigaohm
The following values for input and output capacitors are recommended to reduce output ripple:
Input capacitor (Cin): 4.7uF
Output capacitor (Cout): 10uF