Features and Benefits
- Wide Operating VIN Range: 4.5V to 38V
- RSENSE or DCR Current Sensing
- ±1% 0.8V Reference Accuracy Over Temperature
- 400kHz Switching Frequency
- Dual N-channel MOSFET Synchronous Drive
- Very Low Dropout Operation: 97% Duty Cycle
- Starts Up Into Pre-Biased Output
- Adjustable Output Voltage Soft-Start
- Output Current Foldback Limiting (Disabled During Soft-Start)
- Output Overvoltage Protection
- 5V LDO for External Gate Drive
- OPTI-LOOP® Compensation Minimizes COUT
- Low Shutdown IQ: 15μA
- Tiny Thermally Enhanced 12-Pin 2mm × 3mm DFN and MSOP Packages
The LTC3854 is a high performance synchronous stepdown switching DC/DC controller that drives an all N-channel synchronous power MOSFET stage.
The LTC3854 features a 400kHz constant frequency current mode architecture. The LTC3854 operates from a 4.5V to 38V (40V absolute maximum) input voltage range and regulates the output voltage from 0.8V to 5.5V.
The RUN/SS pin provides both soft-start and enable features. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. Current foldback limits MOSFET dissipation during short circuit conditions. Current foldback functions are disabled during soft-start.
The LTC3854 has a minimum on-time at 75ns, making it well suited for high step-down ratios. The strong onboard MOSFET drivers allow the use of high power external MOSFETs to produce output currents up to 20A.
- Automotive Systems
- Telecom Systems
- Industrial Equipment
- Distributed DC 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.
Evaluation Kits (3)
Demonstration circuit 1450A is a small foot print, high efficiency synchronous buck converter with 4.5V to 26V input range. It can supply 5A maximum load current at 2.5V output. The demo board features the LTC3854EDDB controller. The controller features a 400kHz constant frequency current mode architecture and allows RSENSE or DCR inductor current sensing. The demo board is configured using RSENSE.
Demonstration circuit 1487A is a small foot print, wide input voltage range, high efficiency synchronous buck converter with 4.5V to 34V input range. It can supply 12A maximum load current at 2.5V output. The demo board features the LTC3854EMSE controller. The controller features a 400kHz constant frequency current mode architecture and allows RSENSE or DCR inductor current sensing. The demo board is configured using RSENSE.
Demonstration circuit 1271 is a small foot print, high efficiency synchronous buck converter with 4.5V to 14V input range. It can supply 15A maximum load current at 1.5V output. The demo board features the LTC3854EDDB controller. The controller features a 400kHz constant frequency current mode architecture and allows RSENSE or DCR inductor current sensing. The demo board is configured using RSENSE.
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.
To open the project file for this circuit:
Step 1: Download and install LTpowerCAD on your computer.
Step 2: Click on the link(s) in the section below to download part-specific project files.
Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.
LTpowerCAD Project Files
Design tools for the following parts are available in LTpowerCAD:
Technical Articles (1)
Press Releases (1)
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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.