Features and Benefits
- 2-Phase Operation Reduces Required Input and Output Capacitance and Power Supply Induced Noise
- Synchronous Operation for Highest Efficiency and Reduced Heat Dissipation
- Wide VIN Range: 4.5V to 38V (40V Abs Max) and Operates Down to 2.5V After Start-Up
- Output Voltage Up to 60V
- ±1% 1.200V Reference Voltage
- RSENSE or Inductor DCR Current Sensing
- 100% Duty Cycle Capability for Synchronous MOSFET
- Low Quiescent Current: 135μA
- Phase-Lockable Frequency (75kHz to 850kHz)
- Programmable Fixed Frequency (50kHz to 900kHz)
- Power Good Output Voltage Monitor
- Low Shutdown Current, IQ < 8μA
- Internal LDO Powers Gate Drive from VBIAS or EXTVCC
- Thermally Enhanced Low Profile 28-Pin 4mm × 5mm QFN Package and Narrow SSOP Package
The LTC3787 is a high performance PolyPhase® single output synchronous boost converter controller that drives two N-channel power MOSFET stages out-of-phase. Multiphase operation reduces input and output capacitor requirements and allows the use of smaller inductors than the single-phase equivalent. Synchronous rectification increases efficiency, reduces power losses and eases thermal requirements, enabling high power boost applications.
A 4.5V to 38V input supply range encompasses a wide range of system architectures and battery chemistries. When biased from the output of the boost converter or another auxiliary supply, the LTC3787 can operate from an input supply as low as 2.5V after start-up. The operating frequency can be set for a 50kHz to 900kHz range or synchronized to an external clock using the internal PLL. PolyPhase operation allows the LTC3787 to be configured for 2-, 3-, 4-, 6- and 12-phase operation.
The SS pin ramps the output voltage during start-up. The PLLIN/MODE pin selects Burst Mode® operation, pulse- skipping mode or forced continuous mode at light loads.
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (2)
Demonstration circuit 2001A is a step-up DC/DC converter using two LTC3787EUFD dual-phase synchronous boost controllers in a parallel configuration for high current, high power 4-phase operation. The DC2001A has an input supply voltage range from 6V to 24V. The converter provides an output voltage of 24V, with a very high efficiency output of 25A to 30A.
Demonstration circuit DC1411 is DC/DC boost converter featuring the LTC3787 constant frequency current mode boost controller. The DC1411A operates over 5V to 24V input and provides 6A to 16A of output current. The 350kHz constant frequency operation results in small and efficient circuit. The converter provides high output voltage accuracy (typically ±3%) over wide load range with no minimum load requirement. The demonstration circuit can be easily modified to generate different output voltages.
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.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, 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.
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.
Design tools for the following parts are available in LTpowerCAD:
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.
Sample & Buy
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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.