This module is great solution for the components that uses only 3.3V power, it can supply up to 800mA of current. You can connect it through Arduino's 5V supply or external 5V supply to operate different components.
Featuers
The input voltage must be 1.5V or 2V higher than output voltage, otherwise it can not output enough power.
Do not work above the operating voltage, or it will be damaged easily.
