Pololu 5V, 6A Step-Down Voltage Regulator D24V60F5 Overview 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 6 A. A higher-power version of this regulator with a typical maximum output current of 9 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 A to 20 A 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 regulators 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 160C), 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). Features Input voltage: 5 to 38 V (see below for more details on the regulators dropout voltage, which affects the low end of the operating range) Fixed 5 V output (with 4% accuracy) this can be lowered by adding an external resistor between FB and VOUT Typical maximum continuous output current: 6 A Integrated reverse-voltage protection, over-current protection, over-temperature shutoff, soft-start, and under-voltage lockout Typical efficiency of 80% to 95%, depending on input voltage and load the switching frequency automatically changes at light loads to maintain high efficiencies800 A typical no-load quiescent current can be reduced to 10 A to 20 A per volt on VIN by disabling the board Power good output indicates when the regulator cannot maintain its set output voltage Compact size: 1.6 0.8 0.3 (40.6 20.3 7.6 mm) Four mounting holes for 2 or M2 screws Smaller holes for 0.1 header pins and larger holes for terminal blocks offer several options for connecting to the board Using the regulator Connections This boost regulator has six connections: input voltage (VIN), ground (GND), output voltage (VOUT), feedback (FB), ENABLE, and power good (PG). The input voltage, VIN, powers the regulator and can be supplied with voltages up to 38V. The effective lower limit of VIN is VOUT plus the regulators dropout voltage, which varies approximately linearly with the load from around 500 mV to a little over a volt (see below for graphs of dropout voltages as a function of the load). The output voltage, VOUT, is set to 5V by default. The output voltage can optionally be lowered by adding a resistor between the FB pin and VOUT as detailed in the Decreasing the output voltage section below. The regulator is enabled by default: a 100 k pull-up resistor on the board connects the ENABLE pin to reverse-protected VIN. The ENABLE pin can be driven low (under 0.6 V) to put the board into a low-power state. The quiescent current draw in this sleep mode is dominated by the current in the pull-up resistor from ENABLE to VIN and by the reverse-voltage protection circuit, which will draw between 10 A and 20 A per volt on VIN when ENABLE is held low. If you do not need this feature, you should leave the ENABLE pin disconnected. The power good indicator, PG, is an open-drain output that goes low when the regulators output voltage falls below 90% of what it is set to (i.e. 4.5 V with the default 5 V output setting). An external pull-up resistor is required to use this pin.