LT8705A

Name: LT8705A
Brand: Analog Devices
Price: 8.95 USD
Availability: InStock

RECOMMENDED FOR NEW DESIGNS

80V V_IN and V_OUT Synchronous 4-Switch Buck-Boost DC/DC Controller

Data Sheet Product Selection Table

Part Models: 12
1ku List Price: Starting From $8.95

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Overview

Single Inductor Allows V_IN Above, Below, or Equal to Regulated V_OUT
V_IN Range 2.8V (Need EXTV_CC > 6.4V) to 80V
V_OUT Range: 1.3V to 80V
Quad N-Channel MOSFET Gate Drivers
Synchronous Rectification: Up to 98% Efficiency
Input and Output Current Monitor Pins
Synchronizable Fixed Frequency: 100kHz to 400kHz

Integrated Input Current, Input Voltage, Output Current and Output Voltage Feedback Loops
Improved Light Load Transition from DCM to FCM
Improved IMON_OUT, IMON_IN Offset When Cold
Clock Output Usable To Monitor Die Temperature

The LT8705A is a high performance buck-boost switching regulator controller that operates from input voltages above, below or equal to the output voltage. The part has integrated input current, input voltage, output current and output voltage feedback loops. With a wide 2.8V to 80V input and 1.3V to 80V output range, the LT8705A is compatible with most solar, automotive, telecom and battery-powered systems. The LT8705A is an improved pin compatible version of the LT8705 and is recommended for new designs. See LT8705A vs LT8705 in the Applications Information section for more information.

The LT8705A includes a MODE pin to select among Burst Mode^® operation, discontinuous or continuous conduction mode at light loads. Additional features include a 3.3V/12mA LDO, a synchronizable fixed operating frequency, and onboard gate drivers.



LT8705
LT8705A	Improved, pin-to-pin compatible version of LT8705. Recommended for all new designs

Applications

High Voltage Buck-Boost Converters
Input or Output Current Limited Converters

Part Models: 12
1ku List Price: Starting From $8.95

Documentation

Data Sheet 1

LT8705A: 80V VIN and VOUT Synchronous 4-Switch Buck- Boost DC/DC Controller Data Sheet 10/28/2016

Design Note 2

4-Switch Buck-Boost Controller with Pass-Thru Capability Eliminates Switching Noise 11/01/2019

DN521 - 80V Synchronous 4-Switch Buck-Boost Controller Delivers Hundreds of Watts with 99% Efficiency 09/30/2013

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
LT8705AEFE#PBF	38-Lead TSSOP w/ EP	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8705AEFE#TRPBF	38-Lead TSSOP w/ EP	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8705AEUHF#PBF	38-Lead QFN (5mm x 7mm w/ EP)	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8705AEUHF#TRPBF	38-Lead QFN (5mm x 7mm w/ EP)	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8705AHFE#PBF	38-Lead TSSOP w/ EP	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8705AHFE#TRPBF	38-Lead TSSOP w/ EP	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8705AIFE#PBF	38-Lead TSSOP w/ EP	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8705AIFE#TRPBF	38-Lead TSSOP w/ EP	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8705AIUHF#PBF	38-Lead QFN (5mm x 7mm w/ EP)	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8705AIUHF#TRPBF	38-Lead QFN (5mm x 7mm w/ EP)	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8705AMPFE#PBF	38-Lead TSSOP w/ EP	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys
LT8705AMPFE#TRPBF	38-Lead TSSOP w/ EP	Material Declaration Reliability Report Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

May 18, 2026 - 26_0072 Epoxy Change for Select TSSOP Products
		PCN26_0072_Form Material_Report
LT8705AEFE#PBF	PRODUCTION
LT8705AEFE#TRPBF	PRODUCTION
LT8705AHFE#PBF	PRODUCTION
LT8705AHFE#TRPBF	PRODUCTION
LT8705AIFE#PBF	PRODUCTION
LT8705AIFE#TRPBF	PRODUCTION
LT8705AMPFE#PBF	PRODUCTION
LT8705AMPFE#TRPBF	PRODUCTION
Feb 14, 2025 - 25_0017 Bond Wire Change from Gold to Copper
		PCN25_0017_Form Material_Report
LT8705AEFE#PBF	PRODUCTION
LT8705AEFE#TRPBF	PRODUCTION
Apr 6, 2022 - 22_0068 Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL
		PCN22_0068_Form Material_Report
LT8705AEFE#PBF	PRODUCTION
LT8705AEFE#TRPBF	PRODUCTION
LT8705AHFE#PBF	PRODUCTION
LT8705AHFE#TRPBF	PRODUCTION
LT8705AIFE#PBF	PRODUCTION
LT8705AIFE#TRPBF	PRODUCTION
LT8705AMPFE#PBF	PRODUCTION
LT8705AMPFE#TRPBF	PRODUCTION
Apr 14, 2025 - 25_0017 Bond Wire Change from Gold to Copper
		PCN25_0017_Form Material_Report
LT8705AHFE#PBF	PRODUCTION
LT8705AHFE#TRPBF	PRODUCTION
LT8705AIFE#PBF	PRODUCTION
LT8705AIFE#TRPBF	PRODUCTION
LT8705AIUHF#PBF	PRODUCTION
LT8705AIUHF#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
Hot Swap Controllers 1
LTC4380	RECOMMENDED FOR NEW DESIGNS	Low Quiescent Current Surge Stopper
Ideal Diodes and PowerPath Controllers 1
LTC4359	RECOMMENDED FOR NEW DESIGNS	Ideal Diode Controller with Reverse Input Protection

Parts	Product Life Cycle	Description
LT8390A	RECOMMENDED FOR NEW DESIGNS	60V 2MHz Synchronous 4-Switch Buck-Boost Controller with Spread Spectrum
LT8390	RECOMMENDED FOR NEW DESIGNS	60V Synchronous 4-Switch Buck-Boost Controller with Spread Spectrum

Tools & Simulations

LTspice 2

Models for the following parts are available in LTspice:

LT8705
LT8705A

LTpowerCAD 1

LT8705A Project - 36-80Vin, 48Vo/5A, 200kHz

Design tools for the following parts are available in LTpowerCAD:

LT8705
LT8705A

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.

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.

Evaluation Kits

LT8705AEUHF Demo Board | VIN = 36V to 75V, VOUT = 48V @ 18A

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Product Details

Demonstration circuit 2285A features two high power high performance buck-boost LT8705A converters operating in master-slave configuration. The circuit can operate with input voltages above, below or equal to the output voltage. The demo board input range is 36V to 75V. The output is optimized for 48V at 18A, with the output current limit set at 20A. The circuit will operate with lower input voltage than 36V if load current is reduced.