Features and Benefits
- 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
The LTC3777 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.
- Industrial, Transportation, Medical, Military, Avionics
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
Demonstration circuit 2519A is a high voltage, high efficiency synchronous buck-boost DC/DC converter with a 16V to 120V input voltage range. It can supply a 10A maximum load current with a 48V output. The demo board features the LTC®3777EFE controller. The constant frequency current mode architecture allows a phase-lockable frequency of up to 600kHz, while an optional output current feedback loop provides support for applications such as 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 input range, wide output range and seamless transfers between operation modes, the LTC3777 is ideal for Industrial, Automotive, Medical, Military and Avionics applications.
The light load operation mode of the converter is determined with the MODE pin. Use JP2 jumper to select pulseskipping mode or forced continuous mode (CCM) operation. The switching frequency is pre-set at about 200kHz. The converter can also be externally synchronized to an external clock through the PLLIN pin (PLLIN terminal on the board). To shut down the converter, force the RUN pin below 1.2V (SW1: OFF). The power good output (PGOOD terminal) is low when the output voltage is outside of the ±10% regulation window.
Documentation & Resources
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Models for the following parts are available in LTspice:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
To open the project file for this circuit:
Step 1: Download and install LTpowerCAD on your computer.
Step 2: Click on the link(s) in the section below to download part-specific project files.
Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.
LTpowerCAD Project Files
Design tools for the following parts are available in LTpowerCAD:
LTC3777 Companion Parts
Recommended Related Parts
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.