Features

• Regulated Output with Input Above, Below or Equal to the Output
• Single Inductor, No Schottky Diodes
• High Efficiency: Up to 96%
• 28µA Quiescent Current in Burst Mode® Operation
• Up to 1.2A Continuous Output Current from a Single Lithium-Ion
• True Output Disconnect in Shutdown
• 2.4V to 5.5V Input Range
• 2.4V to 5.25V Output Range
• 600kHz Fixed Frequency Operation
• Synchronizable Oscillator
• Selectable Burst Mode or Fixed Frequency Operation
• <1µA Quiescent Current in Shutdown
• Small, Thermally Enhanced 12-Lead (4mm × 3mm × 0.8mm) DFN package

Typical Application

Description

The LTC3443 is a high efficiency, fixed frequency, buck-boost DC/DC converter that operates from input voltages above, below or equal to the output voltage. The part is pin for pin compatible with its predecessor, the LTC3441, with a lower operating frequency (600kHz), and a V_C pin clamp circuit during Burst Mode operation. The topology incorporated in the IC provides a continuous transfer function through all operating modes, making the product ideal for single Lithium Ion or multi-cell applications where the output voltage is within the battery voltage range.

The device includes two 0.10Ω N-channel MOSFET switches and two 0.11Ω P-channel switches. External Schottky diodes are optional, and can be used for a moderate efficiency improvement. The operating frequency is internally set to 600kHz and can be synchronized up to 1.2MHz. Quiescent current is only 28µA in Burst Mode operation, maximizing battery life in portable applications. Burst Mode operation is user controlled and can be enabled by driving the MODE/SYNC pin high. If the MODE/ SYNC pin is driven low or with a clock, then fixed frequency switching is enabled.

Other features include a 1µA shutdown, soft-start control, thermal shutdown and current limit. The LTC3443 is available in a thermally enhanced 12-lead (4mm × 3mm) DFN Package.