The compact (0.4″ × 0.5″) D24V6F5 switching step-down (or buck) voltage regulator takes an input voltage between 7 V and 42 V and efficiently reduces it to 5 V while allowing for a maximum output current of 600 mA. The pins have a 0.1″ spacing, making this board compatible with standard solderless breadboards and perfboards.
- input voltage: up to 42v
- fixed 5 V output with 4% accuracy
- maximum output current: 600mA
- 2 mA typical no-load quiescent current
- integrated over-temperature shutoff
- small size: 13 × 10 × 3 mm
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 μA, 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 exceed VOUT by at least the regulator’s dropout voltage (see below for graphs of dropout voltages as a function of the load), and you must ensure that noise on your input does not exceed the 42 V maximum. Additionally, please be wary of destructive LC spikes.
The four connections are labeled on the back side of the PCB, and they are arranged with a 0.1″ spacing along the edge of the board for compatibility with solderless breadboards, connectors, and other prototyping arrangements that use a 0.1″ grid. You can solder wires directly to the board or solder in either the 4×1straight male header strip or the 4×1 right-angle male header strip that is included.
Typical Efficiency and Output Current
The efficiency of a voltage regulator, defined as (Power out)/(Power in), is an important measure of its performance, especially when battery life or heat are concerns. As shown in the graphs below, this switching regulator typically has an efficiency of 80 to 90%.
The maximum achievable output current is approximately proportional to the ratio of the input voltage to the output voltage. If the input current exceeds the switch current limit (typically somewhere between 1.4 and 2 A), the output voltage will begin to drop. Additionally, the maximum output current can depend on other factors, including the ambient temperature, air flow, and heat sinking.
LC Voltage Spikes
When connecting voltage to electronic circuits, the initial rush of current can cause damaging voltage spikes that are much higher than the input voltage. In our tests with typical power leads (~30″ test clips), input voltages above 10 V caused voltage spikes in excess of 20 V. You can suppress such spikes by soldering a 33μF or larger electrolytic capacitor close to the regulator between VIN and GND.