LTC3789 - High Efficiency, Synchronous, 4-Switch Buck-Boost Controller

The LTC®3789 is a high performance buck-boost switching regulator controller that operates from input voltages above, below or equal to the output voltage. The constant-frequency, current mode architecture allows a phase-lockable frequency of up to 600kHz, while an output current feedback loop provides support for battery charging. With a wide 4V to 38V (40V maximum) input and output range and seamless, low noise transitions between operating regions, the LTC3789 is ideal for automotive, telecom and battery-powered systems.

The operating mode of the controller is determined through the MODE/PLLIN pin. The MODE/PLLIN pin can select between pulse-skipping mode and forced continuous mode operation and allows the IC to be synchronized to an external clock. Pulse-skipping mode offers high efficiency and low ripple at light loads, while forced continuous mode operates at a constant frequency for noise-sensitive applications.

A PGOOD pin indicates when the output is within 10% of its designed set point. The LTC3789 is available in low profile 28-pin 4mm × 5mm QFN and narrow SSOP packages.

Features
  • Single Inductor Architecture Allows VIN Above, Below or Equal to the Regulated VOUT
  • Programmable Input or Output Current
  • Wide VIN Range: 4V to 38V
  • 1% Output Voltage Accuracy: 0.8V < VOUT < 38V
  • Synchronous Rectification: Up to 98% Efficiency
  • Current Mode Control
  • Phase-Lockable Fixed Frequency: 200kHz to 600kHz
  • No Reverse Current During Start-Up
  • Power Good Output Voltage Monitor
  • Internal 5.5V LDO
  • Quad N-Channel MOSFET Synchronous Drive
  • VOUT Disconnected from VIN During Shutdown
  • True Soft-Start and VOUT Short Protection, Even in Boost Mode
  • Available in 28-Lead QFN (4mm × 5mm) and 28-Lead SSOP Packages
Typical Application

Applications
  • Automotive Systems
  • Distributed DC Power Systems
  • High Power Battery-Operated Devices
  • Industrial Control
Packaging

Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LTC3789EGN#PBFSSOP-28E$6.64$4.65
LTC3789EGN#TRPBFSSOP-28E$4.75
LTC3789EUFD#PBF4x5 QFN-28E$6.64$4.65
LTC3789EUFD#TRPBF4x5 QFN-28E$4.75
LTC3789IGN#PBFSSOP-28I$7.64$5.35
LTC3789IGN#TRPBFSSOP-28I$5.45
LTC3789IUFD#PBF4x5 QFN-28I$7.64$5.35
LTC3789IUFD#TRPBF4x5 QFN-28I$5.45
Demo Boards
Part NumberDescriptionPrice
DC1523ALTC3789EGN Demo Board | 5V VIN 36V, VOUT = 12V @ 5A$200.00
DC1721ALTC4000EGN/LTC3789EGN Demo Board u 14.6V, 5A Battery Charger with 6VIN to 36VIN Buck-Boost Converter$250.00
DC1757ALTC3789EGN Buck-Boost Demo Board | VIN = 6V to 36V, VOUT = 12V @ 12A$200.00
DC1878ALTC3789EGN Demo Board I Vin Range: 8V to 75V, VOUT: 12V @ 5A$200.00
DC1881ALTC3789EUFD Buck-Boost Demo Board | VIN = 6V to 36V, VOUT = 12V @ 2.5AContact Factory
DC2253ALTC3789EGN Demo Board | Sync Buck-Boost, 6V ≤ VIN ≤ 36V; VOUT = 12V @ 25AContact Factory
Datasheet
Application Note
Design Note
Reliability Data
Press Release
LTspice
LTpowerCAD
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