Pololu 5V, 9A Step-Down Voltage Regulator D24V90F5

These high-current step-down (buck) regulators generate a fixed 5 V output from input voltages up to 38 V. They are switching regulators (also called switched-mode power supplies (SMPS) or DC-to-DC converters) and have a typical efficiency between 80% to 95%. The available output current is a function of the input voltage and efficiency (see the Typical Efficiency and Output Current section below), but the input current can typically be as high as 9 A.

A lower-power version of this regulator with a typical maximum output current of 6 A is also available. The two versions of the board look very similar, so the bottom silkscreen includes a blank space where you can add your own distinguishing marks or labels. You should not use the colors of the printing on the tall, cylindrical electrolytic capacitors to differentiate the two versions as these colors are subject to change.

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, and a PG (power good) indicator makes it easy to monitor the state of the main power for your system. The regulator?s output voltage setting can also be lowered by adding an external resistor.

This regulator has built-in reverse-voltage protection, short-circuit protection, thermal shutdown (which typically activates at 160°C), a soft-start feature that reduces inrush current, and an under-voltage lockout that causes the regulator to turn off when the input voltage is below 4.2 V (typical).