Pololu – Adjustable Step-Up Voltage Regulator U1V11A

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