LTC3777 - 150V VIN and VOUT Synchronous 4-Switch Buck-Boost Controller + Switching Bias Supply


  • 4-Switch Current Mode Single Inductor Architecture Allows VIN Above, Below or Equal to VOUT
  • Wide VIN Range: 4.5V to 150V
  • Wide Output Voltage Range: 1.2V ≤ VOUT ≤ 150V
  • Synchronous Rectification: Up to 99% Efficiency
  • ±1% 1.2V Voltage Reference
  • Input or Output Average Current Limit
  • Integrated 12μA IQ, 150V, 85mA, Switching Bias for Optimal Thermal Performance
  • Programmable 6V to 10V DRVCC Optimizes Efficiency
  • No Top FET Refresh Noise in Boost or Buck Mode
  • VOUT Disconnected from VIN During Shutdown
  • Phase-Lockable Fixed Frequency (50kHz to 600kHz)
  • No Reverse Current During Start-Up
  • 150V Rated RUN Pin with Accurate Turn-On Threshold
  • Thermally Enhanced 48-Lead e-LQFP Package

Typical Application

LTC3777 Typical Application
LTC3777 Typical Application


The LTC®3777 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 input/output constant current loop provides support for battery charging. The 150V integrated switching bias supply is a high efficiency step-down regulator that draws only 12μA typical DC supply current with a regulated output voltage at no load.

With a wide 4.5V to 150V input and output range and seamless transfers between operating regions, the LTC3777 is ideal for industrial, telecom and battery powered systems.

The LTC3777 features a power good output indicator and a MODE pin to select between pulse-skipping mode or forced continuous mode of operation. The PLLIN pin allows the IC to be synchronized to an external clock. The SS pin ramps the output voltage during start-up. Current foldback limits MOSFET heat dissipation during short circuit conditions.



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

Part Number Package Code Temp Package
LTC3777ELXE#PBF 7mm x 7mm LQFP-48 LXE E 05-08-1832 Yes
LTC3777ILXE#PBF 7mm x 7mm LQFP-48 LXE I 05-08-1832 Yes

LTC3777 Package Drawing

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
LTC3777ELXE#PBF 7mm x 7mm LQFP-48 E $12.00 $8.40 Yes
LTC3777ILXE#PBF 7mm x 7mm LQFP-48 I $13.14 $9.20 Yes
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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.

Click here to view our complete list of demo boards


  • Industrial, Transportation, Medical, Military, Avionics

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Design Tools

Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:

  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
  • LTpowerCAD - A complete power supply selection, synthesis and design tool
  • LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
  • PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
  • Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
  • LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
  • And More!

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