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

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

LTC3789 Typical Application
LTC3789 Typical Application

Description

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.

Packaging

For complete and up to date package information and drawings, please refer to our packaging page

4x5 QFN-28, SSOP-28

LTC3789 Package Drawing
LTC3789 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LTC3789EGN#PBF SSOP 28 E $6.64 $4.65 View
LTC3789EGN#TRPBF SSOP 28 E $4.75 View
LTC3789EUFD#PBF QFN 28 E $6.64 $4.65 View
LTC3789EUFD#TRPBF QFN 28 E $4.75 View
LTC3789IGN#PBF SSOP 28 I $7.64 $5.35 View
LTC3789IGN#TRPBF SSOP 28 I $5.45 View
LTC3789IUFD#PBF QFN 28 I $7.64 $5.35 View
LTC3789IUFD#TRPBF QFN 28 I $5.45 View
Buy NowRequest Samples
* 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 Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC1523A LTC3789EGN Demo Board | 5V VIN 36V, VOUT = 12V @ 5A $200.00
DC1721A LTC4000EGN/LTC3789EGN Demo Board u 14.6V, 5A Battery Charger with 6VIN to 36VIN Buck-Boost Converter $250.00
DC1757A LTC3789EGN Buck-Boost Demo Board | VIN = 6V to 36V, VOUT = 12V @ 12A $200.00
DC1878A LTC3789EGN Demo Board I Vin Range: 8V to 75V, VOUT: 12V @ 5A $200.00
DC1881A LTC3789EUFD Buck-Boost Demo Board | VIN = 6V to 36V, VOUT = 12V @ 2.5A Contact Factory
DC2253A LTC3789EGN Demo Board | 6V ≤ VIN ≤ 36V; VOUT = 12V @ 25A Contact Factory
Buy Now
Click here to view our complete list of demo boards

Applications

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

Product Notifications

Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.

Forgot your password? Click here.
Need help? Email mylinear@linear.com with questions and comments.

Design Tools

LTpowerCAD

The LTpowerCAD II design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD

Design tools for the following parts are available in LTpowerCAD:
LTC3789

LTspiceIV

LTspice IV is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice IV

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice IV
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice IV does not automatically open after clicking the link above, 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

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice IV:
LTC3789

Technical Support