Features

• Reverse-Battery Protection for DC/DC Converter and Load
• High Efficiency: Up to 94%
• Generates 5V at 175mA from a 1.8V Input
• Operates from 1.8V to 5.5V Input Supply
• 2V to 6V Adjustable Output Voltage
• Inrush Current Controlled During Start-Up
• Output Disconnnect in Shutdown
• Low Noise 1.2MHz PWM Operation
• Tiny External Components
• Automatic Burst Mode® Operation (LTC3499)
• Continuous Switching at Light Loads (LTC3499B)
• Overvoltage Protection
• 8-Lead (3mm × 3mm × 0.75mm) DFN and MSOP Packages

Typical Application

Description

The LTC3499/LTC3499B are synchronous, fixed frequency step-up DC/DC power converters with integrated reverse battery protection that protect and disconnect the devices and load when the battery polarity is reversed while delivering high efficiency in a small (3mm × 3mm) DFN package. True output disconnect eliminates inrush current and allows zero load current in shutdown.

The devices feature an input voltage range of 1.8V to 5.5V enabling operation from two alkaline or NiMH batteries. The switching frequency is internally set at 1.2MHz allowing the use of tiny surface mount inductors and capacitors. A minimal number of external components are required to generate output voltages ranging from 2V to 6V. The LTC3499 features automatic Burst Mode operation to increase efficiency at light loads, while the LTC3499B features continuous switching at light loads.

The soft-start time is externally programmable through a small capacitor. Anti-ring circuitry reduces EMI emissions by damping the inductor in discontinuous mode. The devices feature <1μA shutdown supply current, integrated overvoltage protection and are available in both 8-pin (3mm × 3mm) DFN and 8-pin MSOP packages.