LTC3780 - High Efficiency, Synchronous, 4-Switch Buck-Boost Controller

Features

  • Single Inductor Architecture Allows VIN Above, Below or Equal to VOUT
  • Wide VIN Range: 4V to 36V Operation
  • Synchronous Rectification: Up to 98% Efficiency
  • Current Mode Control
  • ±1% Output Voltage Accuracy: 0.8V < VOUT < 30V
  • Phase-Lockable Fixed Frequency: 200kHz to 400kHz
  • Power Good Output Voltage Monitor
  • Internal LDO for MOSFET Supply
  • Quad N-Channel MOSFET Synchronous Drive
  • VOUT Disconnected from VIN During Shutdown
  • Adjustable Soft-Start Current Ramping
  • Foldback Output Current Limiting
  • Selectable Low Current Modes
  • Output Overvoltage Protection
  • Available in 24-Lead SSOP and Exposed Pad
    (5mm × 5mm) 32-Lead QFN Packages

Typical Application

LTC3780 Typical Application
LTC3780 Typical Application

Description

The LTC3780 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 400kHz. With a wide 4V to 30V (36V maximum) input and output range and seamless transfers between operating modes, the LTC3780 is ideal for automotive, telecom and battery-powered systems.

The operating mode of the controller is determined through the FCB pin. For boost operation, the FCB mode pin can select among Burst Mode® operation, Discontinuous mode and Forced Continuous mode. During buck operation, the FCB mode pin can select among Skip-Cycle mode, Discontinuous mode and Forced Continuous mode. Burst Mode operation and Skip-Cycle mode provide high efficiency operation at light loads while forced continuous mode and discontinuous mode operate at a constant frequency.

Fault protection is provided by an output overvoltage comparator and internal foldback current limiting. A Power Good output pin indicates when the output is within 7.5% of its designed set point.

Protected by U.S. Patents, including 5481178, 6304066, 5929620, 5408150, 6580258, patent pending on current mode architecture and protection

Packaging

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

5x5 QFN-32, SSOP-24

LTC3780 Package Drawing
LTC3780 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LTC3780EG SSOP 24 E $6.64 $4.65 View
LTC3780EG#PBF SSOP 24 E $6.64 $4.65 View
LTC3780EG#TR SSOP 24 E $4.75 View
LTC3780EG#TRPBF SSOP 24 E $4.75 View
LTC3780EUH QFN 32 E $6.64 $4.65 View
LTC3780EUH#PBF QFN 32 E $6.64 $4.65 View
LTC3780EUH#TR QFN 32 E $4.75 View
LTC3780EUH#TRPBF QFN 32 E $4.75 View
LTC3780IG SSOP 24 I $7.64 $5.35 View
LTC3780IG#PBF SSOP 24 I $7.64 $5.35 View
LTC3780IG#TR SSOP 24 I $5.45 View
LTC3780IG#TRPBF SSOP 24 I $5.45 View
LTC3780IUH QFN 32 I $7.64 $5.35 View
LTC3780IUH#PBF QFN 32 I $7.64 $5.35 View
LTC3780IUH#TR QFN 32 I $5.45 View
LTC3780IUH#TRPBF QFN 32 I $5.45 View
LTC3780MPG SSOP 24 MP $10.34 $7.24 View
LTC3780MPG#PBF SSOP 24 MP $10.34 $7.24 View
LTC3780MPG#TR SSOP 24 MP $7.30 View
LTC3780MPG#TRPBF SSOP 24 MP $7.30 View
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* 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
DC1046A LTC3780EG/LTC4440ES6 Demo Board | Vin: 36V to 72V, Vout 48V/5A $225.00
DC1155A LTC3780EUH Demo Board | 6V ≤ VIN ≤ 32V, VOUT = 12V @ 2A $200.00
DC686A LTC3780EG Demo Board | Buck-Boost, 5V to 32Vin, Vout = 12V @ 5A max Contact Factory
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Click here to view our complete list of demo boards

Applications

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

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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:
LTC3780

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:

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:
LTC3780

Technical Support