Features and Benefits
- Single Inductor Architecture Allows VIN Above, Below or Equal to VOUT
- 2.7V to 10V Input and Output Range
- Up to 96% Efficiency
- Up to 10A of Output Current
- All N-channel MOSFETs, No RSENSE™
- True Output Disconnect During Shutdown
- Programmable Current Limit and Soft-Start
- Optional Short-Circuit Shutdown Timer
- Output Overvoltage and Undervoltage Protection
- Programmable Frequency: 100kHz to 1MHz
- Selectable Burst Mode® Operation
- Available in 24-Lead (4mm × 4mm) Exposed Pad QFN Package
The LTC3785 is a high power synchronous buck-boost controller that drives all N-channel power MOSFETs from input voltages above, below and equal to the output voltage. With an input range of 2.7V to 10V, the LTC3785 is well suited for a wide variety of single or dual cell Li-Ion or multicell alkaline/NiMH applications.
The operating frequency can be programmed from 100kHz to 1MHz. The soft-start time and current limit are also programmable. The soft-start capacitor doubles as the fault timer which can program the IC to latch off or recycle after a determined off time. Burst Mode operation is user controlled and can be enabled by driving the MODE pin high.
Protection features include foldback current limit, shortcircuit and overvoltage protection.
- Palmtop Computers
- Handheld Instruments
- Wireless Modems
- Cellular Telephones
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 957 is a wide input range, 3.3V / 3.0A output synchronous buck-boost controller featuring the LTC3785. This circuit was designed to demonstrate the high levels of performance, efficiency, and small solution size attainable using this part in a buck-boost power supply. It operates at 500kHz and produces a regulated 3.3V, 3.0A output from an input voltage range of 2.7 to 10V. It is suitable for portable applications, and has a footprint area that is 0.36 square inches. Synchronous rectification helps to attain efficiency up to 96%, depending on line and load. The LTC3785 provides current limit and shutdown disconnect. It offers Burst Mode® operation for high efficiency at light loads.
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:
LTC3785 Companion Parts
Recommended Related Parts
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.