The S7V7F5 switching step-up/step-down regulator efficiently produces 5 V from input voltages between 2.7 V and 11.8 V. Its ability to convert both higher and lower input voltages makes it useful for applications where the power supply voltage can vary greatly, as with batteries that start above but discharge below 5 V. The very compact (0.35″ × 0.475″) module has a typical efficiency of over 90% and can supply up to 1 A when stepping down and about 500 mA when stepping up.
The Pololu step-up/step-down voltage regulator S7V7F5 is a switching regulator (also called a switched-mode power supply (SMPS) or DC-to-DC converter) that uses a buck-boost topology. It takes an input voltage from 2.7 V to 11.8 V and increases or decreases the voltage to a fixed 5 V output with a typical efficiency of over 90%.
This flexibility in input voltage is especially well-suited for battery-powered applications in which the battery voltage begins above 5 V and drops below as the battery discharges. Without the typical restriction on the battery voltage staying above the required voltage throughout its life, new battery packs and form factors can be considered. For instance, a 4-cell battery holder, which might have a 6 V output with fresh alkalines but a 4.8 V nominal voltage with NiMH cells and a 4.0 V output with partially discharged cells, can now be used for a 5 V circuit. In another typical scenario, a disposable 9V battery powering a 5 V circuit can be discharged to under 3 V instead of cutting out at 6 V, as with typical linear or step-down regulators.
In typical applications, this regulator can deliver about 1 A continuous when the input voltage is higher than 5 V (stepping down) and 500 mA continuous when the input is lower than 5 V (stepping up); please see the graphs at the bottom of this page for a more detailed characterization. The regulator has short-circuit protection, and thermal shutdown prevents damage from overheating; the board does not have reverse-voltage protection.
- input voltage: 2.7 V to 11.8 V
- fixed 5V output with +5/-3% accuracy
- typical continuous output current: 1 A when stepping down; 500 mA when stepping up (Actual continuous output current depends on input voltage. See Typical Efficiency and Output Current section below for details.)
- power-saving feature maintains high efficiency at low currents (quiescent current is less than 0.1 mA)
- integrated over-temperature and short-circuit protection
- small size: 0.35″ × 0.475″ × 0.1″ (9 × 12 × 3 mm)
The step-up/step-down regulator has just three connections: the input voltage (VIN), ground (GND), and the output voltage (VOUT). 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 standard solderless breadboards and perfboards and connectors 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 input voltage, VIN, should be between 2.7 V and 11.8 V. Lower inputs can shut down the voltage regulator; , so you should ensure that noise on your input is not excessive, and you should be wary of destructive LC spikes (see below for more information).
The output voltage, VOUT, is regulated to a fixed 5 V, but it can be as high as 5.2 V when there is little or no load on the regulator.