Pololu 3.3V Step-Up/Step-Down Voltage Regulator S9V11F3S5

The S9V11F3S5 switching step-up/step-down regulator efficiently produces a fixed 3.3 V (default) or 5 V (selectable) output whether it is higher or lower than the input voltage, which can range from 2 V to 16 V. (Note: minimum start-up voltage is 3 V, but it operates to 2 V after that.) The compact (0.5? × 0.6?) module can supply a typical output current of up to 1.5 A when the input voltage is close to the output voltage.