Pololu: #2114

This compact step-up (or boost) regulator generates 3.3 V from voltages as low as 0.8 V and delivers up to 200 mA, making it perfect for powering small 3.3 V electronics projects from one or two NiMH, NiCd, or alkaline cells.

Overview

These tiny boost (step-up) switching regulators are based on the NCP1402 boost regulator IC. Their small dimensions of just 0.33″ × 0.5″ (8.4 mm × 12.7 mm) and a startup voltage of down to 0.8 V make it easy to build 3.3 V and 5 V circuits that are powered by lower battery voltages. The available output current and output voltage ripple depend on the input voltage, but the regulator can provide up to 200 mA if the input voltage is high enough.

With low input voltages, the output voltage ripple is under 40 mV peak-to-peak. When the input voltage is close to the output, 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 the output voltage.

Some example applications include:

• Powering 3.3 V or 5 V systems from lower-voltage batteries.
• Powering higher-voltage subsystems in lower-voltage systems (e.g. powering a 5 V sensor in a 3.3 V system).
• This regulator is available with a fixed 3.3 V or 5 V output.

For higher-power applications, consider using one of our adjustable boost regulators or our U3V12Fx boost regulators. For a regulator that supports similarly low input voltages but higher currents, consider our U1V11x boost regulators, which offer features that the rest of our boost regulators lack, such as a true shutdown and automatic linear down-regulation when the input voltage exceeds the output voltage.

Using the Boost Regulator

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 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 are included.

Features

• Operating voltage: 0.8 V – VOUT
• 3.3 V or 5.0 V output with 2.5% accuracy
• <3 mA typical no-load quiescent current
• Small size: 8.4 mm × 12.7 mm × 3.8 mm (0.33″ × 0.50″ × 0.15″)
• Weight without header pins: 0.6 g (0.02 oz)

Don Luc

Pololu: #2560

This compact (0.45″×0.6″) U1V11A switching step-up (or boost) voltage regulator efficiently boosts input voltages as low as 0.5 V to an adjustable output voltage between 2 V and 5.25 V. Unlike most boost regulators, the U1V11A offers a true shutdown option that turns off power to the load, and it automatically switches to a linear down-regulation mode when the input voltage exceeds the output. The pins have a 0.1″ spacing, making this board compatible with standard solderless breadboards and perfboards.

Overview

This adjustable boost (step-up) voltage regulator generates higher output voltages (between 2 V and 5.25 V) from input voltages as low as 0.5 V, and it also automatically switches to a linear down-regulation mode when the input voltage exceeds the output. This makes it great for powering electronics projects from 1 to 3 NiMH, NiCd, or alkaline cells or from a single lithium-ion cell. Additionally, unlike most boost regulators, this unit offers a true shutdown option that turns off power to the load (with typical boost regulators, the input voltage will pass directly through to the output when they are disabled).

When boosting, this module acts as a switching regulator (also called switched-mode power supplies (SMPS) or DC-to-DC converters) and has a typical efficiency between 70% to 90%. The available output current is a function of the input voltage, output voltage, and efficiency (see Typical Efficiency and Output Current section below), but the input current can typically be as high as 1.2 A. This regulator is also available with a fixed 3.3 V or fixed 5 V output, and very similar regulators are available in a much smaller size with a fixed 3.3 V or fixed 5 V output.

The regulator’s thermal shutdown engages at around 140°C and helps prevent damage from overheating, but it does not have short-circuit or reverse-voltage protection.

Features

• Input voltage: 0.5 V to 5.5 V
• Adjustable output voltage from 2 V to 5.25 V
• True shutdown option that turns off power to the load
• Automatic linear down-regulation when the input voltage is greater than the output voltage
• 1.2 A switch allows for input currents up to 1.2 A
• Good efficiency at light load: <1 mA typical no-load quiescent current, though it can exceed 1 mA for very low input voltages (<100 µA typical quiescent current with SHDN = LOW)
• Integrated over-temperature shutoff
• Small size: 0.45″ × 0.6″; × 0.1″ (11.5 × 15.3 × 2.5 mm)

Don Luc