Features

• Regulated Output with Input Voltages Above, Below or Equal to the Output
• 1.8V to 5.5V (Input) and 5.25V (Output) Voltage Range
• 0.8A Continuous Output Current: VIN > 1.8V
• 2A Continuous Output Current: VIN > 3V
• Single Inductor
• Synchronous Rectification: Up to 96% Efficiency
• Programmable Burst Mode Operation: IQ = 40µA
• Output Disconnect in Shutdown
• Programmable Frequency from 300kHz to 2MHz
• <1µA Shutdown Current
• Small Thermally Enhanced 14-Lead (3mm × 4mm × 0.75mm) DFN package

Typical Application

Description

The LTC3533 is a wide VIN range, highly efficient, fixed frequency, buck-boost DC/DC converter that operates from input voltages above, below or equal to the output voltage. The topology incorporated in the IC provides a continuous transfer function through all operating modes, making the product ideal for single cell lithium-ion/polymer or multi-cell alkaline/NiMH applications where the output voltage is within the input voltage range.

The LTC3533 features programmable Burst Mode operation, extended VIN and VOUT ranges down to 1.8V, and increased output current. Switching frequencies up to 2MHz are programmed with an external resistor. The Burst Mode threshold is programmed with a single resistor from the BURST pin to GND.

Other features include 1µA shutdown current, short circuit protection, programmable soft-start, current limit and thermal shutdown. The LTC3533 is housed in the thermally enhanced 14-lead (3mm × 4mm × 0.75mm) DFN package.