This extremely compact boost regulator generates 5 V from voltages as low as 0.8 V and delivers up to 200 mA, making it perfect for powering small 5V electronics projects from 1 to 3 NiMH, NiCd, or alkaline cells or from a single lithium-ion cell.
This tiny boost switching regulator is based on the NCP1402 boost regulator IC. The tiny dimensions of just 0.33" x 0.5" (8.4 x 12.7 mm) and a startup voltage of down to 0.8 V make it easy to build 5 V circuits that are powered by lower battery voltages. The available output current and output voltage ripple depend on the input voltage. With a 0.8 V input, approximately 5 mA are available before the output voltage begins dropping. The full 200 mA output can be realized from input voltages over approximately 2.7 V. With low input voltages, the output voltage ripple is under 40 mV peak-to-peak; close to 5 V, the output ripple quickly climbs to 150 mV peak-to-peak. Therefore, adding capacitance from the output to ground is recommended for noise-sensitive applications with input voltages close to 5 V.
Some example applications include:
The boost regulator has just three connections: the input voltage, ground, and the output voltage. These three 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 3×1 straight male header strip or the 3×1 right-angle male header strip that is included.
The NCP1402 will effectively remove itself from the circuit, leaving the output connected to the input through the inductor and diode. Since each of these components add a bit of voltage drop, the output voltage becomes a bit under the input voltage. The NCP1402 has an absolute maximum voltage of 6 V, and most 5 V components can take up to 5.25 V or 5.5 V, so this board can be used with four NiMH or NiCd cells, which can reach 5.5 V when fully charged.