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
AEC-Q100 data available for specific packages
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
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LTC3789EGN#PBF | SSOP-28 | GN | E | 05-08-1641 (GN28) | Yes |
| LTC3789EGN#TRPBF | SSOP-28 | GN | E | 05-08-1641 (GN28) | Yes |
| LTC3789EUFD#PBF | 4x5 QFN-28 | UFD | E | 05-08-1712 | Yes |
| LTC3789EUFD#TRPBF | 4x5 QFN-28 | UFD | E | 05-08-1712 | Yes |
| LTC3789IGN#PBF | SSOP-28 | GN | I | 05-08-1641 (GN28) | Yes |
| LTC3789IGN#TRPBF | SSOP-28 | GN | I | 05-08-1641 (GN28) | Yes |
| LTC3789IUFD#PBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
| LTC3789IUFD#TRPBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC3789EGN#PBF | SSOP-28 | E | $6.64 | $4.65 | Yes | |
| LTC3789EGN#TRPBF | SSOP-28 | E | $4.75 | Yes | ||
| LTC3789EUFD#PBF | 4x5 QFN-28 | E | $6.64 | $4.65 | Yes | |
| LTC3789EUFD#TRPBF | 4x5 QFN-28 | E | $4.75 | Yes | ||
| LTC3789IGN#PBF | SSOP-28 | I | $7.64 | $5.35 | Yes | |
| LTC3789IGN#TRPBF | SSOP-28 | I | $5.45 | Yes | ||
| LTC3789IUFD#PBF | 4x5 QFN-28 | I | $7.64 | $5.35 | Yes | |
| LTC3789IUFD#TRPBF | 4x5 QFN-28 | I | $5.45 | Yes | ||
| Buy Now • Request Samples | ||||||
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 | Sync Buck-Boost Controller, 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 | Sync Buck-Boost, 6V ≤ VIN ≤ 36V; VOUT = 12V @ 25A | Contact Factory | |
| Buy Now | |||
Designed for Automotive and Transportation Applications
AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC3789IGN#PBF | SSOP-28 | I | $7.64 | $5.35 | Yes | |
| LTC3789IGN#TRPBF | SSOP-28 | I | $5.45 | Yes | ||
| LTC3789IUFD#PBF | 4x5 QFN-28 | I | $7.64 | $5.35 | Yes | |
| LTC3789IUFD#TRPBF | 4x5 QFN-28 | I | $5.45 | Yes | ||
| Buy Now • Request Samples | ||||||
Applications
- Automotive Systems
- Distributed DC Power Systems
- High Power Battery-Operated Devices
- Industrial Control
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Design Tools
LTspice
LTspice® software 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
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
- Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
- Step 3: If LTspice 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:
LTC3789
LTpowerCAD
The LTpowerCAD 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
To open the project file for this circuit:
- Step 1: If you have not installed LTpowerCAD on this computer, download and install LTpowerCAD
- Step 2: Once LTpowerCAD is installed, click on the link(s) below to open the project file
- Step 3: If LTpowerCAD does not automatically open after clicking the link above, you can open the project file by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTpowerCAD and open the project file by selecting 'Open Project' from the 'File' menu
Design tools for the following parts are available in LTpowerCAD:
LTC3789
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
