Overview
Features and Benefits
- Sub Milliohm DCR Current Sensing
- High Efficiency: Up to 95%
- Selectable Current Sensing Limit
- Programmable DCR Temperature Compensation
- Die Overtemperature Thermal Shutdown
- ± 0.5% 0.6V Output Voltage Accuracy
- Programmable Fixed Frequency 250kHz to 770kHz
- High Speed Differential Remote Sense Amplifier
- Wide Input Voltage Range: 4.5V to 38V
- Output Voltage Range: 0.6V to 3.5V with Diffamp
- Adjustable Soft-Start or Output Voltage Tracking
- Foldback Output Current Limit
- Short-Circuit Soft Recovery
- Output Overvoltage Protection
- 24-Lead (4mm × 4mm) QFN and 24-Lead FE Packages
Product Details
The LTC3866 is a single phase current mode synchronous step-down switching regulator controller that drives all N-channel power MOSFET switches. It employs a unique architecture which enhances the signal-to-noise ratio of the current sense signal, allowing the use of a very low DC resistance power inductor to maximize the efficiency in high current applications. This feature also reduces the switching jitter commonly found in low DCR applications. The LTC3866 also includes a high speed remote sense differential amplifier, a programmable current sense limit that can be selected to 10mV, 15mV, 20mV, 25mV or 30mV, and DCR temperature compensation to limit the maximum output current precisely over temperature.
The LTC3866 also features a precise 0.6V reference with a guaranteed limit of ±0.5% that provides an accurate output voltage from 0.6V to 3.5V. A 4.5V to 38V input voltage range allows it to support a wide variety of bus voltages and various types of batteries.
The LTC3866 is offered in a low profile 24-lead 4mm × 4mm QFN and 24-lead exposed pad FE packages.
Applications
- Computer Systems
- Telecom Systems
- Industrial and Medical Instruments
- DC Power Distribution Systems
Product Lifecycle
Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
Documentation & Resources
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R526 Reliability Data3/26/2018PDF365 K
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DC1829A - Demo Board1/25/2012PDF274K
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Sub 0.2 OHM DCR Sensing Current Mode Controller7/30/2012PDF1M
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LTC3874 Video Product Brief10/15/2018
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LTC3866 Video Product Brief10/15/2018
Tools & Simulations
LTspice
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
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.

Design tools for the following parts are available in LTpowerCAD:
Reference Designs (1)
Design Resources
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.
PCN-PDN Information
Sample & Buy
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Buy Now Pricing
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List Pricing
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Lead Times
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Sampling
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Evaluation Boards
Pricing displayed is based on 1-piece.
Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.
Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.