LT8705 - 80V VIN and VOUT Synchronous 4-Switch Buck- Boost DC/DC Controller

The LT®8705 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 LT8705 is compatible with most solar, automotive, telecom and battery-powered systems.

The LT8705 includes servo pins to indicate which feedback loops are active. The MODE pin selects 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, onboard gate drivers, adjustable UVLO, along with input and output current monitoring with programmable maximum levels.

  • Single Inductor Allows VIN Above, Below, or Equal to Regulated VOUT
  • VIN Range 2.8V (Need EXTVCC > 6.4V) to 80V
  • VOUT 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 and Output Voltage Feedback Loops
  • Clock Output Usable To Monitor Die Temperature
  • Available in 38-Lead (5mm × 7mm) QFN and TSSOP Packages with the TSSOP Modified for Improve Voltage Operation
Typical Application
LT8705 Typical Application
LT8705 Typical Application
  • High Voltage Buck-Boost Converters
  • Input or Output Current Limited Converters
LT8705 Package Drawing
LT8705 Package Drawing
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT8705EUHF#PBF5x7 QFN-38E$8.50$5.95
LT8705EUHF#TRPBF5x7 QFN-38E$6.01
LT8705IUHF#PBF5x7 QFN-38I$9.40$6.58
LT8705IUHF#TRPBF5x7 QFN-38I$6.64
Demo Boards
Part NumberDescriptionPrice
DC1924ALT8705EUHF Demo Board | 36V ≤ VIN ≤ 80V; Vout = 48V @ 5A$250.00
Design Note
Reliability Data
Press Release
CAD Symbol
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LT8705 Footprints and Symbols
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