Features and Benefits
- 1.2MHz Switching Frequency
- Low VCESAT Switches: 330mV at 1.3A
- High Output Voltage: Up to 40V
- Wide Input Range: 2.4V to 16V
- Inverting Capability
- 5V at 630mA from 3.3V Input
- 12V at 320mA from 5V Input
- –12V at 200mA from 5V Input
- Uses Tiny Surface Mount Components
- Low Shutdown Current: <1µA
- Low Profile (0.75mm) 10-Lead 3mm × 3mm DFN Package
The LT3471 dual switching regulator combines two 42V, 1.3A switches with error amplifiers that can sense to ground providing boost and inverting capability. The low VCESAT bipolar switches enable the device to deliver high current outputs in a small footprint. The LT3471 switches at 1.2MHz, allowing the use of tiny, low cost and low profile inductors and capacitors. High inrush current at start-up is eliminated using the programmable soft-start function, where an external RC sets the current ramp rate. A constant frequency current mode PWM architecture results in low, predictable output noise that is easy to filter.
The LT3471 switches are rated at 42V, making the device ideal for boost converters up to ±40V as well as SEPIC and flyback designs. Each channel can generate 5V at up to 630mA from a 3.3V supply, or 5V at 510mA from four alkaline cells in a SEPIC design. The device can be configured as two boosts, a boost and inverter or two inverters.
The LT3471 is available in a low profile (0.75mm) 10-lead 3mm × 3mm DFN package.
- Organic LED Power Supply
- Digital Cameras
- White LED Power Supply
- Cellular Phones
- Medical Diagnostic Equipment
- Local ±5V or ±12V Supply
- TFT-LCD Bias Supply
- xDSL Power Supply
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 1280A is a dual output converter featuring the LT3471EDD in Boost and Inverter configurations. Both converters are powered from the same 4.5V to 10V input source. The Boost converter puts out 12V at 300mA and the Inverter -12V at 200mA. The demo circuit demonstrates small size and low component count. The LT3471 operates with inputs as high as 16V but in this demo board the input is limited by the magnitude of the Boost output. In a Boost converter the input needs to be less than the output. The DC1280A is designed so that the Inverting converter can easily be configured as a Boost. Instructions are included in the schematic. Both circuits are designed to demonstrate the soft start feature, advantages of the 1.2MHz switching frequency and the internal 42V/1.3A switches.
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:
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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.