The VPack boost regulator provides a constant output voltage between 3 and 6.5 V from a lower input voltage between 1 and 4.5 V, such as you might get from a two-cell battery pack. The unit comes configured to produce an output voltage of 5 V, which is required for TTL digital logic, however resistor RF2 can be changed to adjust the output voltage, such as for 3.3 V applications. Please see the VPack datasheet (95k pdf) for further information. The typical output current is less than 300 mA and is a function of the step-up voltage: the greater the step-up voltage, the less current the unit can supply.
The output voltage typically has a ripple of 100 – 150 mV peak-to-peak; the magnitude is also a function of the step-up voltage. If your application cannot tolerate this ripple, you can decrease it by putting a 100 uF tantalum capacitor between the output and ground.
This board can be purchased by itself or compactly attached to 5V 1-AA. This unit is functionally the same as the square VPack boost regulator from Bodhilabs, but the thinner layout might be more desirable for certain applications. For an even smaller, less expensive 5V boost regulator, please consider our 5V boost regulator NCP1402.