Features and Benefits
- 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
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 VC 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.
- Handheld Computers
- Handheld Instruments
- MP3 Players
- Digital Cameras
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration Circuit 755 is a constant-frequency synchronous Buck-Boost converter using the LTC3443. The input range is from 2.4V to 5.5V, making it ideal for single-cell lithium-ion or threecell NiCd/NiMH battery applications. This converter provides up to 95% efficiency, much higher than traditional Buck-Boost converters. For 2.5V minimum input voltage, this converter can provide up to 1A load current. The output voltage is set at 3.3V. A different output voltage in the range of 2.4V to 5.25V can be obtained by changing one of the feedback resistors.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Models for the following parts are available in LTspice:
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.