Detailed parameters:  
     1, the input voltage 3-30V, output can be adjusted between 1.21V-18V (adjustable range for increasing the need for greater adjustable resistor), currently in an equal volume of DC-DC circuit, it is few can achieve such a high voltage. 
     2, the maximum output current of 3A, 2A current recommended to use the following, leaving a certain margin. Without fins and airy case, power up to 20W or so, up to 93% efficiency. 
     3, as is the step-down DC-DC circuit, the input voltage needs to be higher than output voltage 1.5V or more, in order to ensure the stability of the output voltage. 
     4, with short circuit overheating protection, output short circuit is not afraid even if the circuit will automatically protect! Empty load, the static power consumption is only about 6mA. 
     5, ultra-small size: 37x37x14mm. 

Circuit module features:   

high-quality double-sided PCB board with epoxy fiberglass board, selected high-quality surface mount components ensure that the circuit is more safe and secure work. Using fully shielded power inductor core inductor, inductor high current to prevent other problems whistle; entire board single point grounding to ensure low ripple, the output is more stable; board back large copper through thermal vias to connect chip cooling , 2A The following work long hours without additional heat sink; 

Note: In larger current operating state, if the board feels very hot, and it should immediately install the heat sink off, so as to avoid high temperature circuit burned.