Features and Benefits
- Regulated Output with Input Above, Below or Equal to the Output
- Single Inductor, No Schottky Diodes
- High Efficiency: Up to 95%
- 25µA 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
- 1MHz Fixed Frequency Operation
- Synchronizable Oscillator
- Selectable Burst Mode or Fixed Frequency Operation
- <1µA Quiescent Current in Shutdown
- Small, Thermally Enhanced 12-Lead (4mm × 3mm) DFN package
The LTC3441 is a high efficiency, fixed frequency, buck-boost DC/DC converter that operates efficiently 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 lithium ion or multicell 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 1MHz and can be synchronized up to 1.7MHz. Quiescent current is only 25µA 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 LTC3441 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 (2)
Demonstration circuit 773 is a synchronous buck-boost white LED driver featuring the LTC3441 and LTC2050. The board is optimized for 3.9V LED forward voltage output at 1000mA load current and a single lithium-ion input voltage range of 3V to 4.2V. the demo board drives a Luxeon III white LED (included on-chip). With its high 1MHz switching frequency, synchronous buck-boost internal power switches, low quiescent current and thermally enhanced package, the LTC3441 is a very versatile and powerful IC for driving high power white LEDs like the Luxeon III from a lithium-ion battery. The LTC2050 is used for constant current control and to adjust the LED current.
The LED pushbutton is used to manually turn on the LED. The SHDN terminal can be used to program pulses of light from an external source for certain flash applications. The DIM terminal can be used to program the LED for dimmer operation than 1A LED current using a external PWM signal.
Demonstration Circuit 625 is a constant-frequency synchronous Buck-Boost converter using the LTC3441. The input range is from 2.4V to 5.5V, making it ideal for single-cell lithium-ion or three-cell 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. The switching frequency is set at 1MHz, which is a good trade-off between efficiency and size.
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:
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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.