Pololu 5V Step-Up/Step-Down Voltage Regulator S10V4F5

Overview

The Pololu step-up/step-down voltage regulator S10V4F5 is a switching regulator (also called a switched-mode power supply (SMPS) or DC-to-DC converter) with a single-ended primary-inductor converter (SEPIC) topology. It takes an input voltage from 2.5 V to 18 V and increases or decreases the voltage to a fixed 5 V output with a typical efficiency of 70% to 80%.

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. Since it lacks the typical restriction that the battery voltage stay 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 V output with partially discharged cells, can now be used for a 5 V circuit. In another typical scenario, a disposable 9 V 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.

Features

• Input voltage: 2.5 V to 18 V (can be higher than, the same as, or lower than the 5 V output)

• Fixed 5 V output with 4% accuracy

• Typical continuous output current: 400 mA (actual continuous output current depends on input voltage; see Typical Efficiency and Output Current section below for details)

• <2 mA typical no-load quiescent current

• Integrated over-temperature shutoff

• Small size: 0.40" x 0.575" x 0.1" (10 mm x 15 mm x 3 mm)

Using the Regulator

During normal operation, this product can get hot enough to burn you. Take care when handling this product or other components connected to it.

Connections

This step-up/step-down regulator has four connections: shutdown (SHDN), input voltage (VIN), ground (GND), and output voltage (VOUT).

The SHDN pin can be driven low (under 0.4 V) to power down the regulator. The quiescent current in this shutdown mode is dominated by the current in the 10 kΩ pull-up resistor from SHDN to VIN. With SHDN held low, this resistor will draw 0.1 mA per volt on VIN (for example, the shutdown current with a 5 V input will be 0.5 mA). This pin should only ever be driven low or left floating; this can be accomplished with a physical switch that toggles it between ground and disconnected, or electrically with something like a transistor controlled by an I/O line.

The input voltage should be between 2.5 V and 18 V. Lower inputs can shut down the voltage regulator; higher inputs can destroy the regulator, so you should ensure that noise on your input is not excessive and be wary of destructive LC spikes (see below for more information).