This small synchronous switching step-down (or buck) regulator takes an input voltage of up to 38 V and efficiently reduces it to 5 V. The board measures only 0.7″ × 0.8″, but it allows a typical continuous output current of up to 5 A. Typical efficiencies of 85% to 95% make this regulator well suited for high-power applications like powering motors or servos. High efficiencies are maintained at light loads by dynamically changing the switching frequency, and an optional shutdown pin enables a low-power state with a current draw of a few hundred microamps.
This step-down (buck) regulator generates a fixed 5 V output from input voltages up to 38 V. It is a switching regulator (also called a switched-mode power supply (SMPS) or DC-to-DC converter) and has a typical efficiency between 85% to 95%, which is much more efficient than linear voltage regulators, especially when the difference between the input and output voltage is large. The available output current is a function of the input voltage and efficiency (see the Typical Efficiency and Output Current section below), but the output current can typically be as high as 5 A.
At light loads, the switching frequency automatically changes to maintain high efficiencies. The regulator has a typical quiescent current draw of less than 1 mA, and the ENABLE pin can be used to put the board in a low-power state that reduces the quiescent current to approximately 10 µA to 20 µA per volt on VIN.
This regulator has built-in reverse-voltage protection, short-circuit protection, a thermal shutdown feature that helps prevent damage from overheating, a soft-start feature that reduces inrush current, and an under-voltage lockout.
More technical information at Pololu.