LTC3785

PRODUCTION

10V, High Efficiency, Synchronous, No R_SENSE Buck-Boost Controller

Part Models: 4
1ku List Price: Starting From $4.26

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Overview

Single Inductor Architecture Allows V_IN Above, Below or Equal to V_OUT
2.7V to 10V Input and Output Range
Up to 96% Efficiency
Up to 10A of Output Current
All N-channel MOSFETs, No R_SENSE^™
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.


	Power Good
LTC3785	No
LTC3785-1	Yes

Applications

Palmtop Computers
Handheld Instruments
Wireless Modems
Cellular Telephones

Part Models: 4
1ku List Price: Starting From $4.26

Documentation

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. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
LTC3785EUF#PBF	24-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3785EUF#TRPBF	24-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3785IUF#PBF	24-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3785IUF#TRPBF	24-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Jan 20, 2022 - 21_0269 Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products
		PCN21_0269_Form Material_Report Detailed Change Description Qualification Results Summary
LTC3785EUF#PBF	PRODUCTION
LTC3785EUF#TRPBF	PRODUCTION
LTC3785IUF#PBF	PRODUCTION
LTC3785IUF#TRPBF	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Hardware Ecosystem

Parts	Product Life Cycle	Description
Protection Switches & Controllers 1
LTC4417	RECOMMENDED FOR NEW DESIGNS	Prioritized PowerPath^™ Controller

Tools & Simulations

LTspice 1

LTC3785 Demo Circuit - 10W Li-Ion/9V Wall Adapter Buck-Boost Controller (2.7-10V to 3.3V @ 3A)

Models for the following parts are available in LTspice:

LTC3785
LTC3785-1

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.

Evaluation Kits

LTC3785EUF Demo Board | No RSENSE, 2.7V ≤ VIN ≤ 10V, VOUT = 3.3V @ 3A

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Product Details

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.

Resources

DC957A - Design File
9/24/2009

DC957A - Schematic
9/24/2009

DC957A - Demo Manual
9/24/2009

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LTC3785

Overview

Documentation

Data Sheet 1

Reliability Data 1

User Guide 1

Design Note 1

Technical Articles 1

Video 1