Features and Benefits
- Wide VIN Range: 2.2V to 22V
- Internal Boost Provides 6V Gate Drive For VIN Down to 2.2V
- No Sensing Resistor Required
- Dual N-Channel MOSFET Synchronous Drive
- Valley Current Mode Control
- Optimized for High Step-Down Ratio
- Power Good Output Voltage Monitor
- 0.8V Reference
- Three Pin-Selected Current Limit Levels
- Constant Switching Frequency: 300kHz
- Programmable Soft-Start
- Output Voltage Tracking
- Available in 16-Pin 5mm × 3mm DFN
The LT3740 is a synchronous step-down switching regulator controller that drives N-channel power MOSFET stages. The controller uses valley current mode architecture to achieve very low duty cycles with excellent transient response without requiring a sense resistor.
The LT3740 includes an internal step-up converter to provide a bias 7.8V higher than the input voltage for the drive. This enables the part to work from an input voltage as low as 2.2V.
The XREF pin is an external reference input that allows the user to override the internal 0.8V feedback reference with any lower value, allowing full control of the output voltage during operation, output voltage tracking or soft-start.
The LT3740 has three current limit levels that can be chosen by connecting the RANGE pin to ground, open, and input respectively.
- Notebook and Palmtop Computers, PDA
- Portable Instruments
- Distributed Power Systems
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.
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:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
Design tools for the following parts are available in LTpowerCAD:
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.