Pololu Step-Down Voltage Regulator D24V6ALV Overview These adjustable buck (step-down) voltage regulators generate lower, user-adjustable output voltages from a wide input voltage range of 4.5 to 42 V. They are switching regulators (also called switched-mode power supplies (SMPS) or DC-to-DC converters) and have a typical efficiency of 80%, which is much more efficient than linear voltage regulators, especially when the difference between the input and output voltage is large. The output voltage is set using the boards trimmer potentiometer, with the two D24VxALV versions having an available range of approximately 2.5 V to 7.5 V and the two D24VxAHV models having an available range of approximately 4 V to 25 V. Versions with 300 mA and 600 mA maximum output currents are available: We also offer versions of this regulator with fixed output voltages: The regulator has short-circuit protection, and thermal shutdown prevents damage from overheating. The board does not have reverse-voltage protection. If you need more output current, consider our D15V35F5S3 and D15V70F5S3 3.3V/5V step-down voltage regulators, which can typically deliver a continuous 3.5 A and 7 A, respectively. Features input voltage: 4.5 V to 42 V (note: the input voltage should be at least a few volts above the output voltage) output adjustable from 2.5 V to 7.5 V (D24VxALV) or 4 V to 25 V (D24VxAHV) maximum output current of 300 mA (D24V3Axx) or 600 mA (D24V6Axx) 1.25 MHz switching frequency 2 mA typical no-load quiescent current (20 A typical quiescent current with SHDN = 0V) integrated over-temperature and over-current shutoff small size: 0.6 0.4 0.16 (15 10 4 mm) weight without header pins: 0.03 oz (0.8 g) Using the RegulatorConnections The buck regulator has four connections: shutdown (SHDN), input voltage (VIN), ground (GND), and output voltage (VOUT). The SHDN pin can be driven low (under 0.3 V) to turn off the output and put the board into a low- power state that typically draws 20 A, and it can be driven high (above 2.3 V) to enable the board. If you do not need to use the shutdown feature, the SHDN pin can be directly connected to VIN to permanently enable the board. You should not leave this pin disconnected as this can result in unpredictable behavior. The input voltage, VIN, should be between 4.5 V and 42 V. If the input voltage gets too close to the output voltage, the output will start to drop, so you should ensure that VIN is at least a few volts above VOUT. You should also ensure that noise on your input does not exceed the 42 V maximum, and you should be wary of destructive LC spikes (see below for more information). The output voltage, VOUT, is determined by the trimmer potentiometer position. Setting the output voltage to be higher than the input voltage will not damage the board, but it will produce an oscillating output rather than a clean power rail (see the oscilloscope capture below), so we recommend you avoid setting the output voltage to be higher than the input voltage. The available output voltage range depends on your input voltage, VIN, and the regulator version you have: 2.5 V to 7.5 V (D24VxALV) or 4 V to 25 V (D24VxAHV). The maximum available output current also depends on your regulator version: 300 mA (D24V3Axx) or 600 mA (D24V6Axx). Exceeding the maximum output current can cause the output voltage to drop below its set value. VOUT of the Pololu step-down regulator D24V3ALV when VIN is 5 V and the output voltage setting is higher than 5 V.