Features and Benefits
- Optimized Features for WCDMA Handsets
- Regulated Output with Input Voltages Above, Below, or Equal to the Output
- 0.5V to 5V Output Range
- Up to 400mA Continuous Output Current From a Single Lithium-Ion Cell
- Minimal External Components
- 1.5MHz Fixed Frequency Operation
- Internal Loop Compensation for Fast Response <25μs Full Scale Output Slewing; COUT 4.7μF
- Output Disconnect in Shutdown
- 2.75V to 5.5V Input
- <1μA Shutdown Current
- Internal Soft-Start
- Output Overvoltage Protection
- Single Inductor, No Schottky Diodes Required
- Small, Thermally Enhanced 8-Lead (3mm × 3mm) DFN Package
The LTC3444 is a highly efficient, fixed frequency, buck-boost DC/DC converter, which operates from input voltages above, below, and 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 a single Lithium-Ion or multi-cell applications where the output voltage can vary over a wide range.
The LTC3444 has been optimized for use in 3G WCDMA applications. A unique design yields high efficiency at very low output voltages while also eliminating external components. The high speed error amplifier provides the fast transient response required to slew the RF power amplifier from standby to transmit and transmit to stand by power levels. Output overvoltage protection protects the RF power amplifier.
Operating frequency is internally set to 1.5MHz to minimize external component size while maximizing efficiency.
Other features include <1μA shutdown current, internal soft-start, peak current limit and thermal shutdown. The LTC3444 is available in a small, thermally enhanced 8-lead (3mm × 3mm) DFN package.
- WCDMA Applications–3G Handsets with High Speed Data Rate Capability
- 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 901A features the LTC3444 and is a highly efficient, 1.5MHz fixed frequency buck-boost DC/DC converter. The input voltage can range from 3.1V to 5.0V and is suitable for Li-Ion or three-cell NiCd/NiMH battery applications while the output voltage can be set anywhere from 0.8V to 4.2V by injecting a 0.35V to 2.4V control signal. The demo board provides up to 400mA of output current.
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.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
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.